Explosives Based on Hydrogen Peroxide With Improved Sleep Time

ABSTRACT

The present invention provides an explosive composition comprising hydrogen peroxide, fuel and one or more density stabilisers. The present invention also provides methods for preparing the compositions and method of using the compositions.

FIELD OF THE INVENTION

The present invention relates to improved hydrogen peroxide-basedexplosives. The invention has been developed primarily for use as ahydrogen peroxide/fuel-based explosive composition for use in miningapplications and will be described hereinafter with reference to thisapplication. However, it will be appreciated that the invention is notlimited to this particular field of use.

BACKGROUND OF THE INVENTION

The following discussion of the prior art is provided to place theinvention in an appropriate technical context and enable the advantagesof it to be more fully understood. It should be appreciated, however,that any discussion of the prior art throughout the specification shouldnot be considered as an express or implied admission that such prior artis widely known or forms part of common general knowledge in the field.

Nearly all commercial and mining explosives used in the world today arebased on ammonium nitrate (AN) or combinations of AN with smallerquantities of other alkaline and/or alkaline earth nitrate salts, e.g.sodium nitrate (SN) or calcium nitrate (CN). AN, which is a strongoxidiser, has been used as the base of commercial explosives for atleast the last 50-60 years. Most explosives of this type rely on theenergetic reaction of nitrogen compounds incorporated within theexplosive to provide the necessary explosive power.

Initially, mining companies used AN as an explosive on its own. However,they soon realised that the addition of diesel increased the energyoutput without a large increase on costs (ammonium nitrate-fuel oil, nowcommonly referred to as ‘ANFO’). However, the water resistance of ANFOis quite poor, which limited its use in wet blast holes. To amelioratethis issue, slurries and watergels were developed. Slurries typicallycomprise AN dissolved/dispersed in water, and other salts such ascalcium nitrate, sodium nitrate, amine nitrates, perchlorates, etc. andother additives such as guar gum (as thickener) and water soluble orinsoluble fuels (glycerol, MMAN, diesel, etc). They can also be blendedwith ANFO depending on the characteristics of the ground being blasted.Slurries also typically include solid sensitisers (aluminium and highexplosives such as TNT, RDX, etc) to enable the slurry to detonate andto minimise misfires. Watergels have similar compositions to slurries,however, crosslinkers can be added to enhance the water resistance ofthe product.

One of the drawbacks of watergels and slurries is that there is a limitof AN which can be incorporated into the solution. This drawback wasovercome by the development of water-in-oil emulsions. These emulsionscan contain AN in high concentration (see U.S. Pat. No. 3,447,978) asemulsions are manufactured at high temperatures. Water-in-oil emulsionsare made of a hot aqueous phase (composed of AN, other nitrate salts,perchlorate salts, etc.) dispersed into an organic fuel. Theaqueous-organic mixture is stabilised by the use of an emulsifier.Emulsions can also be blended with ANFO in different ratios so suit theground to be blasted.

Despite the development of AN emulsions, AN slurries, and watergels,however, there is still a need to develop improved explosives, which aremore cost effective compared to existing explosive compositions and arecapable of being produced in large quantities to meet the high demandfrom industry. It would be advantageous to use less AN in theformulation and instead use other types of nitrates to providealternatives to the usage of AN. Additionally, such substitutes shouldpreferably be safer, have a relatively low carbon footprint, able to bemanufactured nearby the point of use to minimise the transport on publicroads, able to be manufactured on an as-needs basis to minimise the needfor stockpiling and to increase safety, allow for the use of existingdelivery equipment, and/or produce a lower amount of (or no) toxicnitrogen oxide fumes (NO_(x)) upon detonation, etc. It would also beideal if there are no onerous regulatory requirements for such asubstitute, thereby reducing administrative costs. It would also bepreferable for the explosive composition to be crosslinkable in-situ toincrease viscosity down the blasthole.

Despite the advances on the types of compositions that can bemanufactured from ammonium nitrate, one of the disadvantages is thatduring the detonation NO_(x) fumes can be generated, due to the presenceof nitrogen compounds in the explosive composition (from nitrates).These NO_(x) fumes are toxic and can affect the health of mine sitepersonnel. Therefore, the emission of NO_(x) fume after blasting is asafety issue and, in countries like Australia, there are now strictregulatory controls in place to manage such emissions. See for example“Queensland Guidance Note: Management of oxides of nitrogen in open cutblasting” issued by the regulator in Queensland, Australia, 2011.Likewise, explosive manufacturers in Australia have also issued a codeof practice to manage the NO_(x) fumes after blasting (AEISG Code ofPractice, Prevention and Management of Blast Generated NO_(x) Gases inSurface Blasting, 2011). Therefore, there is a need to find explosivecompositions that substantially reduce the production of NO_(x).

One material that is also an oxidiser and that has the potential to meetat least some of these needs is hydrogen peroxide (H₂O₂).H₂O₂/fuel-based explosives for mining operations generally consist ofthe combination of H₂O₂ with about 5 to about 15 percent of its weightof a liquid carbon-based fuel such as glycerol, fuel oil, and the like.However, it has been observed that, in some cases, H₂O₂-based explosivesare less than ideal where sleep-time above 24 hours is required, as ithas been observed that the density changes over time, which can affectparameters such as the velocity of detonation (VOD).

It is an object of the present invention to overcome or ameliorate oneor more of the disadvantages of the prior art, or at least to provide auseful alternative.

It is an object of preferred forms of the invention to provide aH₂O₂/fuel-based explosive that has improved sleep time. Preferredexplosive compositions of the invention have substantially maintainedsensitivity, density, and VOD over an extended sleep time, which can bein the range of 24 to 48 hours, or even longer. The improved explosivecompositions of the invention can be safely employed in mines due toextended sleep-time, and in some embodiments enable blasts to beundertaken that are not possible with prior art H₂O₂-based explosivecompositions that do not have the extended sleep time as per thecompositions of the present invention. In particular, compositions ofthe invention enable much larger blasts to be undertaken, as theinventive explosive compositions described herein have substantiallymaintained VOD over an extended period of time in the blast hole.

A preferred objective of an embodiment of the present invention is toprovide an explosive composition which meets one or more of thefollowing objectives: is conveniently prepared, has improved densitystability over time in situ, can use large amounts of sustainable fuels(which lowers the carbon footprint of the explosive), and in somepreferred embodiments can use large amount of nitrates other than AN(which lowers the dependency on AN), and enables much larger blasts dueto extended sleep time.

A further preferred objective of the present invention is tosubstantially maintain the density of the explosive composition whenloaded into the blast hole, thereby substantially maintaining the sleeptime for days, and potentially for weeks.

SUMMARY OF THE INVENTION

The present invention relates to explosives for use in commercial,construction, civil, agriculture, mining, and similar fields. However,it will be appreciated that the invention could be utilised in otherrelated fields.

It has now surprisingly been discovered that H₂O₂-based explosivecompositions, when treated or modified with density stabilisers (i.e.,phosphonates), display improved sleep time over prior art H₂O₂-basedexplosive compositions. Further, it has been surprisingly found thatonly relatively small quantities of phosphonates provide the improveddensity stability and sleep time. Without wishing to be bound by anytheory, the inventor considers that the density stabiliser employed inthe present invention acts to prevent additional bubbles of entrainedsensitiser gas to spontaneously form, whereas without a densitystabiliser existing sensitiser bubbles tend to increase in volume andnumber over time.

In the practice of the present invention, phosphonates, usually inliquid form, are added to the H₂O₂ prior to the addition of fuel.Thickeners may be added to the combination of the oxidiser/fuel mixture.

Generally, one or more density stabilisers are incorporated in an amountof up to about 15% w/w of the explosives composition, for example about0.01% w/w to about 10% w/w, e.g. about 1 to about 5% w/w, such as about1 to about 3% w/w. Thereafter, the density-stabilised H₂O₂-basedexplosive can be handled, loaded, and fired in identical fashion toother explosives.

According to a first aspect, the present invention provides an explosivecomposition comprising:

-   -   a. H₂O₂;    -   b. fuel; and    -   c. one or more density stabilisers.

According to a second aspect, the present invention provides a method ofpreparing an explosive composition according to the first aspect, themethod comprising: combining H₂O₂, fuel and one or more densitystabilisers and optionally one or more other oxidisers and/or asensitiser.

According to a third aspect, the present invention provides use of anexplosive composition according to the first aspect to break and moveground, e.g. in mining operations.

According to a fourth aspect, the present invention provides the use ofone or more density stabilisers to improve the sleep time of anexplosive composition in reactive or metalliferous ground, wherein theexplosive composition comprises H₂O₂ and fuel.

In a related aspect, the present invention consists of a method oftreating an explosive composition to improve its long-term stability(sleep time), the method comprising the step of combining a densitystabiliser with said explosive composition to stabilise the density ofthe explosive composition, wherein the explosive composition comprisesH₂O₂ and fuel. In a related aspect, the present invention comprises theuse of a density stabiliser for improving the long-term stability of anexplosive composition. The density stabiliser is used in adensity-stabilising concentration.

The present invention relates to an explosive which substantially avoidsthe release of unwanted NO_(x) fumes upon detonation into the atmospheresurrounding the blasting site. A preferred objective of the presentinvention is to reduce and preferably eliminate nitrogen containingingredients from the explosive composition. It will be appreciated thatwith little or no nitrogen present in the explosive virtually no NO_(x)is released into the atmosphere, or a substantially reduced amount isreleased. The present invention relates to explosives for use incommercial, construction, agriculture, mining, and similar fields.However, it will be appreciated that the invention could be utilised inother related fields.

The density is maintained by including a density stabiliser. The densitystabiliser retains the density of the explosive composition to within+/−0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2, 3, 4, 5, 6, 7,8, 9, 10, 12, 14, 16, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,35, 40, or 50% of its initial density, and/or the density of theexplosive composition within 5, 10, 15, 20, 30 or 60, 90 or 120 minutesof being loaded into the blast hole. The density is preferablymaintained (or stabilised) over a period of up to 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, or 14 days. The density stabiliser preferablymaintains the VOD to within +/−0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,0.9, 1.0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, 30, 35, 40, or 50% of the initial VOD, or theVOD of the explosive composition within 5, 10, 15, 20, 30, 60, 90 or 120minutes of being loaded into the blast hole. The VOD is preferablymaintained over a period of up to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, or 14 days.

The compositions of the invention have a predictable and controllablechange in density and VOD over time. For example, at certainconcentrations of density stabiliser, the density reduces by around 5%per day to around 10% per day, causing a corresponding drop of around 5%to 10% per day in VOD. This enables the drill and blast engineer toprovide a predetermined VOD after a certain sleep time, as the quantityof density stabiliser can be selected to control change in density overthat sleep time. It will be appreciated that, in some prior artcompositions, the density reduces by around 10% per day to around 30%per day, causing a corresponding drop of around 10% to 30% per day inVOD.

Preferably the composition further includes other additives, such asfuel, water, thickeners, emulsifiers, mechanical sensitisation,chemically-derived sensitisation, injected gases, etc, as discussedfurther below. In one preferred embodiment the composition comprises nocomponents which lead to the production of NO_(x) in the after-blastfumes. However, in other embodiments components are added which resultin minimal NO_(x) in the after-blast fumes.

Whilst the preferred explosive oxidiser of the invention is hydrogenperoxide, it will be appreciated that other oxidiser salts or peroxidederivatives can be used with the invention, as partial replacements ofH₂O₂. Non-limiting examples include nitrates salts, perchlorates salts,sodium/potassium peroxide, etc.

Definitions

In describing and claiming the present invention, the followingterminology will be used in accordance with the definitions set outbelow. It is also to be understood that the terminology used herein isfor the purpose of describing particular embodiments of the inventiononly and is not intended to be limiting. Unless defined otherwise, alltechnical and scientific terms used herein have the same meaning ascommonly understood by one having ordinary skill in the art to which theinvention pertains.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words ‘comprise’, ‘comprising’, and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of‘including, but not limited to’.

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients or reaction conditions usedherein are to be understood as modified in all instances by the term‘about’. The examples are not intended to limit the scope of theinvention. In what follows, or where otherwise indicated, ‘%’ will mean‘weight %’, ‘ratio’ will mean ‘weight ratio’ and ‘parts’ will mean‘weight parts’.

Unless the context clearly indicates otherwise, all references to acomponent being present at a certain % w/w are with respect to theentire explosive composition. For example, an explosive compositioncomprising 2-25% w/w hydrogen peroxide refers to an explosivecomposition comprising 2-25 g hydrogen peroxide per 100 g of theexplosive composition.

The term H₂O₂ is an abbreviation for hydrogen peroxide.

The term AN means ammonium nitrate.

CN means calcium nitrate tetra hydrate.

CAN means calcium ammonium nitrate

SN is an abbreviation for sodium nitrate.

ANFO is an abbreviation for ammonium nitrate fuel oil.

Amine nitrates is an abbreviation for monomethylamine or ethyl amine orpropyl amine nitrate.

Sensitiser means an additive that introduces voids in the composition.Sensitisers enable and increase the sensitivity to detonation ofenergetic materials. The sensitiser can be chemically generated voids(gas bubbles) or can enclose or entrap a gas (examples of which includeceramic/glass microballoons, EPS and polyurethane foams).

GMB is an abbreviation for glass micro balloons.

EPS is an abbreviation for expanded polystyrene.

TNT means trinitrotoluene.

HMX refers to octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine.

RDX refers to 1,3,5-trinitroperhydro-1,3,5-triazine.

VOD refers to velocity of detonation in m/sec.

OB means oxygen balance.

The term g/cm³ is has the same meaning as g/ml.

Phosphonates are organic compounds with C-P bonds, such as C—PO(OH)₂ orC—PO(OR)₂ groups. “Phosphonate” as used herein also includes phosphonatesalts comprising phosphonate anions with counter-cations (e.g. sodiumsalts). “Phosphonate” includes mono-phosphonates as well asbis-phosphonates and higher phosphonates. The R group of a phosphonateis not limited to alkyl and can, for example, include heteroatoms (e.g.N).

DTPMPA.Na.x mean diethylenetriamine pentamethylene phosphonic acidsodium salt (C₉H_(28-x)N₃O₁₅P₅Na_(x), CAS no. 22042-96-2).

The term phosphate refers to chemical derivatives of phosphoric acid.The phosphate ion (PO₄₃—) is the conjugate base of phosphoric acid andcan form many different salts. Organophosphates have the generalstructure O═P(OR)₃, wherein the R groups can be the same or different. Rincludes alkyl and aryl. Phosphates comprise COP bonds and lack the C-Pbonds present in phosphonates.

The term “stannate” refers to compounds containing tin (II), (IV) or(VI) and oxygen.

Sleep time is understood as the time between explosives being loadedinto a blast hole and their initiation. The period is typically days.

The terms ‘preferred’, ‘preferably’ and ‘suitably’ refer to embodimentsof the invention that may afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances.

Furthermore, the recitation of one or more preferred embodiments doesnot imply that other embodiments are not useful, and is not intended toexclude other embodiments from the scope of the invention.

The terms ‘a’, ‘an’ and ‘the’ mean ‘one or more’, unless expresslyspecified otherwise. The terms ‘an embodiment’, ‘embodiment’,‘embodiments’, ‘the embodiment’, ‘the embodiments’, ‘an embodiment’,‘some embodiments’, ‘an example embodiment’, ‘at least one embodiment’,‘one or more embodiments’ and ‘one embodiment’ mean ‘one or more (butnot necessarily all) embodiments of the present invention(s)’ unlessexpressly specified otherwise.

The terms “subterranean” or “sub-surface” refers to areas below exposedearth and areas below earth covered by water such as fresh water andsalt water.

The term “optionally substituted” as used throughout the specificationdenotes that the group may or may not be further substituted or fused(so as to form a condensed polycyclic system), with one or morenon-hydrogen substituent groups. In certain embodiments the substituentgroups are one or more groups independently selected from the groupconsisting of halogen, ═O, ═S, —CN, —NO₂, —CF₃, —OCF₃, alkyl, alkenyl,alkynyl, haloalkyl, haloalkenyl, haloalkynyl, heteroalkyl, cycloalkyl,cycloalkenyl, heterocycloalkyl, heterocycloalkenyl, aryl, heteroaryl,cycloalkylalkyl, heterocycloalkylalkyl, heteroarylalkyl, arylalkyl,cycloalkylalkenyl, heterocycloalkylalkenyl, arylalkenyl,heteroarylalkenyl, cycloalkylheteroalkyl, heterocycloalkylheteroalkyl,arylheteroalkyl, heteroarylheteroalkyl, hydroxy, hydroxyalkyl, alkyloxy,alkyloxyalkyl, alkyloxycycloalkyl, alkyloxyheterocycloalkyl,alkyloxyaryl, alkyloxyheteroaryl, alkyloxycarbonyl, alkylaminocarbonyl,alkenyloxy, alkynyloxy, cycloalkyloxy, cycloalkenyloxy,heterocycloalkyloxy, heterocycloalkenyloxy, aryloxy, phenoxy, benzyloxy,heteroaryloxy, arylalkyloxy, amino, alkylamino, acylamino, aminoalkyl,arylamino, sulfonylamino, sulfinylamino, sulfonyl, alkylsulfonyl,arylsulfonyl, aminosulfonyl, sulfinyl, alkylsulfinyl, arylsulfinyl,aminosulfinylaminoalkyl, —C(═O)OH, —C(═O)R^(e), —C(═O)OR^(e),C(═O)NR^(e)R^(f), C(═NOH)R^(e), C(═NR^(e))NR^(f)R^(g), NR^(e)R^(f),NReC(═O)R^(f), NR^(e)C(═O)OR^(f), NR^(e)C(═O)NR^(f)R^(g),NR^(e)C(═NR^(f))NR^(g)R^(h), NR^(e)SO₂R^(f), —SR^(e), SO₂NR^(e)R^(f),—OR^(e), OC(═O)NR^(e)R^(f), OC(═O)R^(e) and acyl,

-   -   wherein R^(e), R^(f), R^(g) and R^(h) are each independently        selected from the group consisting of H, C₁-C₁₂alkyl,        C₁-C₁₂haloalkyl, C₂-C₁₂alkenyl, C₂-C₁₂alkynyl,        C₁-C₁₀heteroalkyl, C₃-C₁₂cycloalkyl, C₃-C₁₂cycloalkenyl,        C₁-C₁₂heterocycloalkyl, C₁-C₁₂heterocycloalkenyl, C₆-C₁₈aryl,        C₁-C₁₈heteroaryl, and acyl, or any two or more of Ra, R^(b),        R^(c) and R^(d), when taken together with the atoms to which        they are attached form a heterocyclic ring system with 3 to 12        ring atoms.

In some embodiments each optional substituent is independently selectedfrom the group consisting of: halogen, ═O, ═S, —CN, —NO₂, —CF₃, —OCF₃,alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, haloalkynyl,heteroalkyl, cycloalkyl, cycloalkenyl, heterocycloalkyl,heterocycloalkenyl, aryl, heteroaryl, hydroxy, hydroxyalkyl, alkyloxy,alkyloxyalkyl, alkyloxyaryl, alkyloxyheteroaryl, alkenyloxy, alkynyloxy,cycloalkyloxy, cycloalkenyloxy, heterocycloalkyloxy,heterocycloalkenyloxy, aryloxy, heteroaryloxy, arylalkyl,heteroarylalkyl, arylalkyloxy, amino, alkylamino, acylamino, aminoalkyl,arylamino, sulfonyl, alkylsulfonyl, arylsulfonyl, aminosulfonyl,aminoalkyl, —COOH, —SH, and acyl.

Examples of particularly suitable optional substituents include F, C,Br, I, CH₃, CH₂CH₃, OH, OCH₃, CF₃, OCF₃, NO₂, NH₂, and CN.

In the definitions of a number of substituents below it is stated that“the group may be a terminal group or a bridging group”. This isintended to signify that the use of the term is intended to encompassthe situation where the group is a linker between two other portions ofthe molecule as well as where it is a terminal moiety. Using the termalkyl as an example, some publications would use the term “alkylene” fora bridging group and hence in these other publications there is adistinction between the terms “alkyl” (terminal group) and “alkylene”(bridging group). In the present application no such distinction is madeand most groups may be either a bridging group or a terminal group.

“Acyl” means an R—C(═O)— group in which the R group may be an alkyl,cycloalkyl, heterocycloalkyl, aryl or heteroaryl group as definedherein. Examples of acyl include acetyl and benzoyl. The group may be aterminal group or a bridging group. If the group is a terminal group itis bonded to the remainder of the molecule through the carbonyl carbon.

“Acylamino” means an R—C(═O)—NH— group in which the R group may be analkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl group as definedherein. The group may be a terminal group or a bridging group. If thegroup is a terminal group it is bonded to the remainder of the moleculethrough the nitrogen atom.

“Alkenyl” as a group or part of a group denotes an aliphatic hydrocarbongroup containing at least one carbon-carbon double bond and which may bestraight or branched preferably having 2-12 carbon atoms, morepreferably 2-10 carbon atoms, most preferably 2-6 carbon atoms, in thenormal chain. The group may contain a plurality of double bonds in thenormal chain and the orientation about each is independently E or Z. Thealkenyl group is preferably a 1-alkenyl group. Exemplary alkenyl groupsinclude, but are not limited to, ethenyl, propenyl, butenyl, pentenyl,hexenyl, heptenyl, octenyl and nonenyl. The group may be a terminalgroup or a bridging group.

“Alkenyloxy” refers to an alkenyl-O— group in which alkenyl is asdefined herein. Preferred alkenyloxy groups are C₁-C₆ alkenyloxy groups.The group may be a terminal group or a bridging group. If the group is aterminal group it is bonded to the remainder of the molecule through theoxygen atom.

“Alkyl” as a group or part of a group refers to a straight or branchedaliphatic hydrocarbon group, preferably a C₁-C₁₂ alkyl, more preferablya C₁-C₁₀ alkyl, most preferably C₁-C₆ unless otherwise noted. Examplesof suitable straight and branched C₁-C₆ alkyl substituents includemethyl, ethyl, n-propyl, 2-propyl, n-butyl, sec-butyl, t-butyl, hexyl,and the like. The group may be a terminal group or a bridging group.

“Alkylamino” includes both mono-alkylamino and dialkylamino, unlessspecified. “Mono-alkylamino” means an Alkyl-NH— group, in which alkyl isas defined herein. “Dialkylamino” means a (alkyl)₂N— group, in whicheach alkyl may be the same or different and are each as defined hereinfor alkyl. The alkyl group is preferably a C₁-C₆alkyl group. The groupmay be a terminal group or a bridging group. If the group is a terminalgroup it is bonded to the remainder of the molecule through the nitrogenatom.

“Alkylaminocarbonyl” refers to a group of the formula(Alkyl)_(x)(H)_(y)NC(═O)— in which alkyl is as defined herein, x is 1 or2, and the sum of X+Y=2. The group may be a terminal group or a bridginggroup. If the group is a terminal group it is bonded to the remainder ofthe molecule through the carbonyl carbon.

“Alkyloxy” refers to an alkyl-O— group in which alkyl is as definedherein. Preferably the alkyloxy is a C₁-C₆alkyloxy. Examples include,but are not limited to, methoxy and ethoxy. The group may be a terminalgroup or a bridging group.

“Alkyloxyalkyl” refers to an alkyloxy-alkyl- group in which the alkyloxyand alkyl moieties are as defined herein. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the alkyl group.

“Alkyloxyaryl” refers to an alkyloxy-aryl- group in which the alkyloxyand aryl moieties are as defined herein. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the aryl group.

“Alkyloxycarbonyl” refers to an alkyl-O—C(═O)— group in which alkyl isas defined herein. The alkyl group is preferably a C₁-C₆ alkyl group.Examples include, but are not limited to, methoxycarbonyl andethoxycarbonyl. The group may be a terminal group or a bridging group.If the group is a terminal group it is bonded to the remainder of themolecule through the carbonyl carbon.

“Alkyloxycycloalkyl” refers to an alkyloxy-cycloalkyl- group in whichthe alkyloxy and cycloalkyl moieties are as defined herein. The groupmay be a terminal group or a bridging group. If the group is a terminalgroup it is bonded to the remainder of the molecule through thecycloalkyl group.

“Alkyloxyheteroaryl” refers to an alkyloxy-heteroaryl- group in whichthe alkyloxy and heteroaryl moieties are as defined herein. The groupmay be a terminal group or a bridging group. If the group is a terminalgroup it is bonded to the remainder of the molecule through theheteroaryl group.

“Alkyloxyheterocycloalkyl” refers to an alkyloxy-heterocycloalkyl- groupin which the alkyloxy and heterocycloalkyl moieties are as definedherein. The group may be a terminal group or a bridging group. If thegroup is a terminal group it is bonded to the remainder of the moleculethrough the heterocycloalkyl group.

“Alkylsulfinyl” means an alkyl-S—(═O)— group in which alkyl is asdefined herein. The alkyl group is preferably a C₁-C₆ alkyl group.Exemplary alkylsulfinyl groups include, but not limited to,methylsulfinyl and ethylsulfinyl. The group may be a terminal group or abridging group. If the group is a terminal group it is bonded to theremainder of the molecule through the sulfur atom.

“Alkylsulfonyl” refers to an alkyl-S(═O)₂— group in which alkyl is asdefined above. The alkyl group is preferably a C₁-C₆alkyl group.Examples include, but not limited to methylsulfonyl and ethylsulfonyl.The group may be a terminal group or a bridging group. If the group is aterminal group it is bonded to the remainder of the molecule through thesulfur atom.

“Alkynyl” as a group or part of a group means an aliphatic hydrocarbongroup containing a carbon-carbon triple bond and which may be straightor branched preferably having from 2-12 carbon atoms, more preferably2-10 carbon atoms, more preferably 2-6 carbon atoms in the normal chain.Exemplary structures include, but are not limited to, ethynyl andpropynyl. The group may be a terminal group or a bridging group.

“Alkynyloxy” refers to an alkynyl-O— group in which alkynyl is asdefined herein. Preferred alkynyloxy groups are C₁-C₆alkynyloxy groups.The group may be a terminal group or a bridging group. If the group is aterminal group it is bonded to the remainder of the molecule through theoxygen atom.

“Aminoalkyl” means an NH₂-alkyl- group in which the alkyl group is asdefined herein. The group may be a terminal group or a bridging group.If the group is a terminal group it is bonded to the remainder of themolecule through the alkyl group.

“Aminosulfonyl” means an NH₂—S(═O)₂— group. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the sulfur atom.

“Aryl” as a group or part of a group denotes (i) an optionallysubstituted monocyclic, or fused polycyclic, aromatic carbocycle (ringstructure having ring atoms that are all carbon) preferably having from5 to 12 atoms per ring. Examples of aryl groups include phenyl,naphthyl, and the like; (ii) an optionally substituted partiallysaturated bicyclic aromatic carbocyclic moiety in which a phenyl and aC₅₋₇cycloalkyl or C₅₋₇cycloalkenyl group are fused together to form acyclic structure, such as tetrahydronaphthyl, indenyl or indanyl. Thegroup may be a terminal group or a bridging group. Typically an arylgroup is a C₆-C₁₈ aryl group.

“Arylalkenyl” means an aryl-alkenyl- group in which the aryl and alkenylare as defined herein. Exemplary arylalkenyl groups include phenylallyl.The group may be a terminal group or a bridging group. If the group is aterminal group it is bonded to the remainder of the molecule through thealkenyl group.

“Arylalkyl” means an aryl-alkyl- group in which the aryl and alkylmoieties are as defined herein. Preferred arylalkyl groups contain aC₁₋₅alkyl moiety. Exemplary arylalkyl groups include benzyl, phenethyl,1-naphthalenemethyl and 2-naphthalenemethyl. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the alkyl group.

“Arylalkyloxy” refers to an aryl-alkyl-O— group in which the alkyl andaryl are as defined herein. The group may be a terminal group or abridging group. If the group is a terminal group it is bonded to theremainder of the molecule through the oxygen atom.

“Arylamino” includes both mono-arylamino and di-arylamino unlessspecified. Mono-arylamino means a group of formula arylNH—, in whicharyl is as defined herein. Di-arylamino means a group of formula(aryl)₂N— where each aryl may be the same or different and are each asdefined herein for aryl. The group may be a terminal group or a bridginggroup. If the group is a terminal group it is bonded to the remainder ofthe molecule through the nitrogen atom.

“Arylheteroalkyl” means an aryl-heteroalkyl- group in which the aryl andheteroalkyl moieties are as defined herein. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the heteroalkyl group.

“Aryloxy” refers to an aryl-O— group in which the aryl is as definedherein. Preferably the aryloxy is a C₆-C₁₈aryloxy, more preferably aC₆-C₁₀aryloxy. The group may be a terminal group or a bridging group. Ifthe group is a terminal group it is bonded to the remainder of themolecule through the oxygen atom.

“Arylsulfonyl” means an aryl-S(═O)₂— group in which the aryl group is asdefined herein. The group may be a terminal group or a bridging group.If the group is a terminal group it is bonded to the remainder of themolecule through the sulfur atom.

A “bond” is a linkage between atoms in a compound or molecule. The bondmay be a single bond, a double bond, or a triple bond.

“Cycloalkenyl” means a non-aromatic monocyclic or multicyclic ringsystem containing at least one carbon-carbon double bond and preferablyhaving from 5-10 carbon atoms per ring. Exemplary monocycliccycloalkenyl rings include cyclopentenyl, cyclohexenyl or cycloheptenyl.The cycloalkenyl group may be substituted by one or more substituentgroups. A cycloalkenyl group typically is a C₃-C₁₂ alkenyl group. Thegroup may be a terminal group or a bridging group.

“Cycloalkyl” refers to a saturated monocyclic or fused or spiropolycyclic, carbocycle preferably containing from 3 to 9 carbons perring, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and thelike, unless otherwise specified. It includes monocyclic systems such ascyclopropyl and cyclohexyl, bicyclic systems such as decalin, andpolycyclic systems such as adamantane. A cycloalkyl group typically is aC₃-C₁₂ alkyl group. The group may be a terminal group or a bridginggroup.

“Cycloalkylalkyl” means a cycloalkyl-alkyl- group in which thecycloalkyl and alkyl moieties are as defined herein. Exemplarymonocycloalkylalkyl groups include cyclopropylmethyl, cyclopentylmethyl,cyclohexylmethyl and cycloheptylmethyl. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the alkyl group.

“Cycloalkylalkenyl” means a cycloalkyl-alkenyl- group in which thecycloalkyl and alkenyl moieties are as defined herein. The group may bea terminal group or a bridging group. If the group is a terminal groupit is bonded to the remainder of the molecule through the alkenyl group.

“Cycloalkylheteroalkyl” means a cycloalkyl-heteroalkyl- group in whichthe cycloalkyl and heteroalkyl moieties are as defined herein. The groupmay be a terminal group or a bridging group. If the group is a terminalgroup it is bonded to the remainder of the molecule through theheteroalkyl group.

“Cycloalkyloxy” refers to a cycloalkyl-O— group in which cycloalkyl isas defined herein. Preferably the cycloalkyloxy is a C₁-C₆cycloalkyloxy.Examples include, but are not limited to, cyclopropanoxy andcyclobutanoxy. The group may be a terminal group or a bridging group. Ifthe group is a terminal group it is bonded to the remainder of themolecule through the oxygen atom.

“Cycloalkenyloxy” refers to a cycloalkenyl-O— group in which thecycloalkenyl is as defined herein. Preferably the cycloalkenyloxy is aC₁-C₆cycloalkenyloxy. The group may be a terminal group or a bridginggroup. If the group is a terminal group it is bonded to the remainder ofthe molecule through the oxygen atom.

“Haloalkyl” refers to an alkyl group as defined herein in which one ormore of the hydrogen atoms has been replaced with a halogen atomselected from the group consisting of fluorine, chlorine, bromine andiodine. A haloalkyl group typically has the formulaC_(n)H_((2n+1−m))X_(m) wherein each X is independently selected from thegroup consisting of F, Cl, Br and I. In groups of this type n istypically from 1 to 10, more preferably from 1 to 6, most preferably 1to 3. m is typically 1 to 6, more preferably 1 to 3. Examples ofhaloalkyl include fluoromethyl, difluoromethyl and trifluoromethyl.

“Haloalkenyl” refers to an alkenyl group as defined herein in which oneor more of the hydrogen atoms has been replaced with a halogen atomindependently selected from the group consisting of F, Cl, Br and I.

“Haloalkynyl” refers to an alkynyl group as defined herein in which oneor more of the hydrogen atoms has been replaced with a halogen atomindependently selected from the group consisting of F, Cl, Br and I.

“Halogen” represents chlorine, fluorine, bromine or iodine.

“Heteroalkyl” refers to a straight- or branched-chain alkyl grouppreferably having from 2 to 24 carbons, 2 to 18 carbons, 2 to 14carbons, 2 to 12 carbons, 2 to 6 carbons in the chain, in which one ormore of the carbon atoms (and any associated hydrogen atoms) are eachindependently replaced by a heteroatomic group selected from S, O, P andNR′ where R′ is selected from the group consisting of H, optionallysubstituted C₁-C₁₂alkyl, optionally substituted C₃-C₁₂cycloalkyl,optionally substituted C₆-C₁₈aryl, and optionally substitutedC₁-C₁₈heteroaryl. Exemplary heteroalkyls include alkyl ethers, secondaryand tertiary alkyl amines, amides, alkyl sulfides, and the like.Examples of heteroalkyl also include hydroxyC₁-C₆alkyl,C₁-C₆alkyloxyC₁-C₆alkyl, aminoC₁-C₆alkyl, C₁-C₆alkylaminoC₁-C₆alkyl, anddi(C₁-C₆alkyl)aminoC₁-C₆alkyl. The group may be a terminal group or abridging group.

“Heteroalkyloxy” refers to a heteroalkyl-O— group in which heteroalkylis as defined herein. Preferably the heteroalkyloxy is aC₂-C₆heteroalkyloxy. The group may be a terminal group or a bridginggroup.

“Heteroaryl” either alone or part of a group refers to groups containingan aromatic ring (preferably a 5 or 6 membered aromatic ring) having oneor more heteroatoms as ring atoms in the aromatic ring with theremainder of the ring atoms being carbon atoms. Suitable heteroatomsinclude nitrogen, oxygen and sulphur. The group may be a monocyclic orbicyclic heteroaryl group. Examples of heteroaryl include thiophene,benzothiophene, benzofuran, benzimidazole, benzoxazole, benzothiazole,benzisothiazole, naphtho[2,3-b]thiophene, furan, isoindolizine,xantholene, phenoxatine, pyrrole, imidazole, pyrazole, pyridine,pyrazine, pyrimidine, pyridazine, tetrazole, indole, isoindole,1H-indazole, purine, quinoline, isoquinoline, phthalazine,naphthyridine, quinoxaline, cinnoline, carbazole, phenanthridine,acridine, phenazine, thiazole, isothiazole, phenothiazine, oxazole,isooxazole, furazane, phenoxazine, 2-, 3- or 4-pyridyl, 2-, 3-, 4-, 5-,or 8- quinolyl, 1-, 3-, 4-, or 5- isoquinolinyl 1-, 2-, or 3- indolyl,and 2-, or 3-thienyl. A heteroaryl group is typically a C₁-C₁₈heteroarylgroup. The group may be a terminal group or a bridging group.

“Heteroarylalkyl” means a heteroaryl-alkyl group in which the heteroaryland alkyl moieties are as defined herein. Preferred heteroarylalkylgroups contain a lower alkyl moiety. Exemplary heteroarylalkyl groupsinclude pyridylmethyl. The group may be a terminal group or a bridginggroup. If the group is a terminal group it is bonded to the remainder ofthe molecule through the alkyl group.

“Heteroarylalkenyl” means a heteroaryl-alkenyl- group in which theheteroaryl and alkenyl moieties are as defined herein. The group may bea terminal group or a bridging group. If the group is a terminal groupit is bonded to the remainder of the molecule through the alkenyl group.

“Heteroarylheteroalkyl” means a heteroaryl-heteroalkyl- group in whichthe heteroaryl and heteroalkyl moieties are as defined herein. The groupmay be a terminal group or a bridging group. If the group is a terminalgroup it is bonded to the remainder of the molecule through theheteroalkyl group.

“Heteroaryloxy” refers to a heteroaryl-O— group in which the heteroarylis as defined herein. Preferably the heteroaryloxy is aC₁-C₁₈heteroaryloxy. The group may be a terminal group or a bridginggroup. If the group is a terminal group it is bonded to the remainder ofthe molecule through the oxygen atom.

“Heterocyclic” refers to saturated, partially unsaturated or fullyunsaturated monocyclic, bicyclic or polycyclic ring system containing atleast one heteroatom selected from the group consisting of nitrogen,sulfur and oxygen as a ring atom. Examples of heterocyclic moietiesinclude heterocycloalkyl, heterocycloalkenyl and heteroaryl.

“Heterocycloalkenyl” refers to a heterocycloalkyl group as definedherein but containing at least one double bond. A heterocycloalkenylgroup typically is a C₂-C₁₂heterocycloalkenyl group. The group may be aterminal group or a bridging group.

“Heterocycloalkyl” refers to a saturated monocyclic, bicyclic, orpolycyclic ring containing at least one heteroatom selected fromnitrogen, sulfur, oxygen, preferably from 1 to 3 heteroatoms in at leastone ring. Each ring is preferably from 3 to 10 membered, more preferably4 to 7 membered. Examples of suitable heterocycloalkyl substituentsinclude pyrrolidyl, tetrahydrofuryl, tetrahydrothiofuranyl, piperidyl,piperazyl, tetrahydropyranyl, morphilino, 1,3-diazapane, 1,4-diazapane,1,4-oxazepane, and 1,4-oxathiapane. A heterocycloalkyl group typicallyis a C₂-C₁₂heterocycloalkyl group. The group may be a terminal group ora bridging group.

“Heterocycloalkylalkyl” refers to a heterocycloalkyl-alkyl- group inwhich the heterocycloalkyl and alkyl moieties are as defined herein.Exemplary heterocycloalkylalkyl groups include(2-tetrahydrofuryl)methyl, (2-tetrahydrothiofuranyl) methyl. The groupmay be a terminal group or a bridging group. If the group is a terminalgroup it is bonded to the remainder of the molecule through the alkylgroup.

“Heterocycloalkylalkenyl” refers to a heterocycloalkyl-alkenyl- group inwhich the heterocycloalkyl and alkenyl moieties are as defined herein.The group may be a terminal group or a bridging group. If the group is aterminal group it is bonded to the remainder of the molecule through thealkenyl group.

“Heterocycloalkylheteroalkyl” means a heterocycloalkyl-heteroalkyl-group in which the heterocycloalkyl and heteroalkyl moieties are asdefined herein. The group may be a terminal group or a bridging group.If the group is a terminal group it is bonded to the remainder of themolecule through the heteroalkyl group.

“Heterocycloalkyloxy” refers to a heterocycloalkyl-O— group in which theheterocycloalkyl is as defined herein. Preferably theheterocycloalkyloxy is a C₁-C₆heterocycloalkyloxy. The group may be aterminal group or a bridging group. If the group is a terminal group itis bonded to the remainder of the molecule through the oxygen atom.

“Heterocycloalkenyloxy” refers to a heterocycloalkenyl-O— group in whichheterocycloalkenyl is as defined herein. Preferably theHeterocycloalkenyloxy is a C₁-C₆ Heterocycloalkenyloxy. The group may bea terminal group or a bridging group. If the group is a terminal groupit is bonded to the remainder of the molecule through the oxygen atom.

“Hydroxyalkyl” refers to an alkyl group as defined herein in which oneor more of the hydrogen atoms has been replaced with an OH group. Ahydroxyalkyl group typically has the formula C_(n)H_((2n+1−x))(OH)_(x).In groups of this type n is typically from 1 to 10, more preferably from1 to 6, most preferably 1 to 3. x is typically 1 to 6, more preferably 1to 3.

“Sulfinyl” means an R—S(═O)— group in which the R group may be OH,alkyl, cycloalkyl, heterocycloalkyl; aryl or heteroaryl group as definedherein. The group may be a terminal group or a bridging group. If thegroup is a terminal group it is bonded to the remainder of the moleculethrough the sulfur atom.

“Sulfinylamino” means an R—S(═O)—NH— group in which the R group may beOH, alkyl, cycloalkyl, heterocycloalkyl; aryl or heteroaryl group asdefined herein. The group may be a terminal group or a bridging group.If the group is a terminal group it is bonded to the remainder of themolecule through the nitrogen atom.

“Sulfonyl” means an R—S(═O)₂— group in which the R group may be OH,alkyl, cycloalkyl, heterocycloalkyl; aryl or heteroaryl group as definedherein. The group may be a terminal group or a bridging group. If thegroup is a terminal group it is bonded to the remainder of the moleculethrough the sulfur atom.

“Sulfonylamino” means an R—S(═O)₂—NH— group. The group may be a terminalgroup or a bridging group. If the group is a terminal group it is bondedto the remainder of the molecule through the nitrogen atom.

The prior art referred to in this specification is incorporated hereinby reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 is a graph showing the results of Example 1, showing the changeof gel density (g·cm⁻³) over time (days) with range ofdensity-stabilised H₂O₂ employing the phosphonate, DTMPMA.Na.X (% w/w).

FIG. 2 is a graph showing the results of Example 1, showing loss of geldensity (% to initial) compared to initial density over time (days) withrange of density-stabilised H₂O₂ employing the phosphonate, DTMPMA.Na.X(% w/w).

FIG. 3 is a graph showing the results of Example 2, showing averagedVelocity of Detonation (VOD) for varying densities of 3% w/w DTMPMAenhanced H₂O₂/glycerol-based explosive formula in unconfined detonations(n=3) in 47 mm diameter tubing, sensitised with 3M™ K15 GlassMicro-Balloons, and initiated with a 25 g Pentex D Booster. Two VODmonitors, VOD1 (dotted line) and VOD2 (dashed line) were attached toeach shot, average for VOD data displayed as solid line.

FIG. 4 is a graph showing the change in gel density (g·cm⁻³) over tendays between 0-5% w/w PA. Error bars are Standard Deviation (n=4). 3, 4,& 5% w/w PA formulations collapsed at 5 days.

FIG. 5 is a graph showing the loss of gel density (%) compared toinitial density over 10 days between 0-5% w/w PA. Error bars areStandard Deviation (n=4). 3, 4, & 5% w/w PA formulations collapsed at 5days.

FIG. 6 is a graph showing the change in gel density (g·cm⁻³) over 13days between 0-2% w/w PA. Error bars are Standard Deviation (n=4).

FIG. 7 is a graph showing the loss of gel density (%) compared toinitial density over 13 days between 0-2% w/w PA. Error bars areStandard Deviation (n=4).

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an explosive composition comprising:

a. H₂O₂;

b. fuel; and

c. one or more density stabilisers.

In one embodiment, the compositions of the invention are formulated aswatergels. In an alternative embodiment, the compositions of theinvention are formulated as emulsions.

Hydrogen Peroxide (H₂O₂)

The preferred concentration of H₂O₂ in the composition of the inventionis between about 2% to 85% by weight. By way of example only, aconcentrated H₂O₂ solution can be sourced (70% w/w) and diluted down to25% w/w for use in the composition. Other possibilities will be apparentto the skilled person. Preferably the H₂O₂ concentration in thecomposition is around 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40, 45, 50, 55, 60, 65,70, 75, 80, or 85% (w/w). Preferably the H₂O₂ concentration in thecomposition is around between about 2 to 3, 3 to 5, 5 to 10, 10 to 15,15 to 20, 20 to 25, 25 to 30, 30 to 35, 35 to 40, 40 to 45, 45 to 50, 50to 55, 55 to 60, 60 to 65, 65 to 70, 70 to 75, 75 to 80, or 80 to 85%(w/w).

It will be understood that the % w/w of hydrogen peroxide present in thecomposition refers the amount of pure hydrogen peroxide. As hydrogenperoxide is provided in the form of an aqueous solution having an H₂O₂concentration of less than 100%, for example, having an H₂O₂concentration of 50% w/w, or 35% w/w, or 30% w/w, the skilled personwill readily understand the need and manner by which they can adjust theamount of diluted H₂O₂ solution required to ensure the explosivecompositions of the invention comprise 2 to 25% w/w H₂O₂. To take anexample for the avoidance of doubt, if a composition of the inventioncontains 20% of a 50% w/w solution of H₂O₂, the composition contains 10%w/w H₂O₂. The skilled person will also appreciate that the 2 to 85% w/wconcentration of H₂O₂ is the final H₂O₂ concentration in the explosivecomposition, and thus account must be taken of the diluting effects ofany other components (e.g., fuels, oxidisers, thickeners, etc.) added tothe composition during formulation.

Water

The explosive compositions described herein may comprise water. In oneembodiment, the explosive composition may comprise less than 50% w/w ofwater, or 40% w/w or less of water, or 30% w/w or less of water, forexample 25% w/w or less, 20% w/w or less, 15% w/w or less or 10% w/w orless. In one embodiment, the explosive composition may comprise 5% w/wor more of water, for example 10% w/w or more. The composition may thuscomprise between 5 and 50% w/w water, or between 5 and 20% w/w water, orbetween 15 and 30% w/w water, or between 10 and 40% w/w water, or 50,45, 40, 35, 30, 25, 20, 15, 10, 5 or 1% w/w water.

Sensitisers

The explosive composition according to the invention may comprise one ormore sensitisers dispersed in the composition to produce voids whichimprove sensitivity to detonation. In addition, H₂O₂ may itself act asboth a sensitiser and an oxidiser. Alternatively, H₂O₂ itself may act asthe sensitiser and no other sensitisers may be used.

Sensitisers include gas bubbles generated in situ or injected air orair/gas entrapped material. Another example of sensitisation is thecombination of both gas bubbles (chemically generated and or injected)and air entrapped material.

The explosive compositions of the present invention comprise adiscontinuous gaseous component to sensitise the composition.

The present invention relies on sensitisation of a H₂O₂-basedcomposition to result in an explosive composition, and to control keyfactors such as explosive sensitivity, density, velocity of detonation(VOD) and the delivery of the energy.

Preferably the explosive composition of the invention is adapted toretain the sensitiser in a substantially homogenous dispersion (e.g. bya thickener or an emulsifier in the case of a watergel or an emulsion,respectively). It will be appreciated that a variety of techniques canbe utilised to achieve this property, as discussed further below.

Preferably a minimum concentration of sensitiser is included into thecomposition to cause it to be explosive. Preferably the sensitiser isincluded in a detonation-sensitive concentration or amount. Thesensitiser is also preferably maintained in a detonation-sensitivedispersion/distribution throughout the composition. Preferably the finaldensity of the composition is controlled into an initial preferredpre-determined explosive range. Preferably the final density iscontrolled with sensitiser to about 0.6 to about 1.15 g/ml. Preferablythe density of the composition is formulated to be around 0.1, 0.2, 0.3,0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or 1.4 g/ml. Preferablythe density of the composition is formulated to be initially betweenaround 0.1 to 0.2, 0.2 to 0.3, 0.3 to 0.4, 0.4 to 0.5, 0.5 to 0.6, 0.6to 0.7, 0.7 to 0.8, 0.8 to 0.9, 0.9 to 1.0, 1.0 to 1.1, 1.1 to 1.2, 1.2to 1.3, 1.3 to 1.4, or 1.4 to 1.5 g/ml. However, it will be appreciatedthat for some applications other high density additives can specificallybe included to increase the density, up to 1.6, 1.7, 1.8, 1.9 or 2.0g/ml. Preferably the density is maintained or stabilised as discussedabove over an extended period of time, thereby increasing sleep timecompared to the explosive composition not including a density stabiliseras discussed herein.

The skilled person will appreciate that a mathematical conversion willbe required to convert the weight of mechanical sensitisers, such asceramic/glass/plastic micro balloons or expanded polystyrene spheres orthe amount of chemical to be decomposed into bubbles to yield a certaindensity, to volume (for void spaces). However, irrespective of the typeof sensitisation, it will be appreciated that the final density iscontrolled to a predetermined value to yield an explosive compositionand to thereby control the parameters discussed above.

Many advantages result from the inventive explosive compositions taughtherein. For example, certain formulations of the compositions of theinvention are more cost effective compared to existing explosivecompositions, and are capable of being produced in large quantities tomeet the demand from the mining industry. The explosive compositions ofthe invention utilise H₂O₂, which is a sustainably-produced materialthat has a relatively low carbon footprint compared to other typesoxidisers used in the art. The explosive compositions of the inventioncan also be formulated into slurry, prilled, beaded, or emulsion form.It will also be appreciated that the compositions of the inventionproduce reduced amounts of NO_(x), and in preferred forms of theinvention no NO_(x) at all. Other advantages include the stabilisationof density over an extended period of time (compared to not including adensity stabiliser as described herein), thereby improving sleep timeand enabling blasts to be conducted that are not possible withH₂O₂-based explosive compositions that do not include a densitystabiliser.

Once the explosive is sensitised, it can be initiated by aprimer/booster, which as the skilled person will be aware is anexplosive which generates a high detonation pressure which theninitiates detonation of the sensitised explosive.

The introduction of voids into the composition can be provided by avariety of techniques (by entrapping gas bubbles when mixing, by usinggas bubbles chemically generated in situ, by injecting gas bubbles, ormixing the composition with gas entrapped material), which are allapplicable to the present invention.

Examples of air entrapped material for sensitisation for hydrogenperoxide-based explosives that can be used in conjunction with gasbubbles are glass or plastic microballoons, expanded polystyrene beads,polyurethane foam, etc.

Preferably the void component is incorporated into the compositions ofthe present invention as fine gas bubbles dispersed throughout thecomposition. Hollow gas-filled compressible particles such as microballoons, or porous particles, or mixtures thereof can also be included.

The discontinuous phase of fine gas bubbles may be incorporated into thecompositions of the present invention by mechanical agitation, injectionby bubbling the gas through the composition, or by in situ generation ofthe gas by chemical means.

Suitable chemicals for the in situ generation of gas bubbles includeH₂O₂ itself which can be decomposed with manganese (Mn) salts, yeast,iodide salts, etc; nitrogen-based compounds such as, for example, sodiumnitrite, nitrosoamines such as, for example,N,N′dinitrosopentamethylenetetramine; boron-based compounds such as, forexample, sodium borohydride; carbonates such as, for example, sodiumcarbonate. Decomposition in situ of a portion of the hydrogen peroxidewith permanganates (or the like) forms oxygen gas bubbles. Decompositionof carbonates with acid in situ to forms carbon dioxide bubbles.

Examples of suitable hollow particles include small hollow microspheresof glass and resinous materials such as phenol-formaldehyde,poly(vinylidene chloride)/poly(acrylonitrile) copolymers andureaformaldehyde. Examples of suitable hollow particles include Q-Cel,Cenospheres, Expancel, 3M, Extendospheres, etc.

Examples of porous materials include expanded minerals such as perlite,fly ash or hollow particles that are a by-product of coal fired powerstations Typically, sufficient void space/gas bubbles (potentially alsoincluding hollow particles and/or porous particles) are used in thecompositions of the present invention to give an explosive compositionhaving a density in the range of from 0.1 to 1.4 g/cm³. In preferredembodiments, the sensitisation is provided entirely from gas bubbles,with the proviso that there are no hollow gas-filled compressibleparticles.

Using conventional mixing techniques to provide bubbles in emulsionexplosive compositions often produce bubbles with a range of bubblesizes. For example, the bubbles often have diameters up to 2000 micronsand average bubble diameters of less than 50 microns are also common. Bychoice of suitable surfactants bubbles of smaller or larger diameterscan be produced. Thus, by choice of an appropriate surfactant at adesired concentration the mean gas bubble diameter in the discontinuousgas phase may be controlled, and bubbles of 50 to 200 microns arepossible. It will be appreciated that the bubble size influences theoverall density, and if low densities are required 50 to 100 microns gasbubbles are preferred. For emulsified explosives the density range ispreferably around 0.60-1.20 g/ml, and for watergels the density range ispreferably between 0.2-1.2 g/ml. In an emulsified system the gas bubblesare preferably 10-100 times larger than the disperse phase droplets. Theoily phase is likely to be in contact the gas bubble, whereas theoxidiser (or discontinuous phase) does not.

As discussed above, the introduction of gas bubbles can be provided by avariety of techniques, which are all applicable to the presentinvention.

In one embodiment the bubbles may be ‘trapped’ during the preparation ofthe explosive composition or by their formation through a chemicalreaction. In U.S. Pat. No. 3,400,026 a formulation which uses protein insolution (albumin, collagen, soy protein, etc.) in order to favour theformation of bubbles and their stabilisation is described. U.S. Pat. No.3,582,411 describes a watergel explosive formulation which contains afoaming agent of the guar gum type modified by hydroxy groups. In U.S.Pat. No. 3,678,140 a process for the incorporation of air by means ofthe use of protein solution is described, by passing the compositionthrough a series of openings at pressures from 40 to 200 psi andsimultaneously introducing air through eductors.

Incorporation of gas bubbles by means of their generation as a result ofa chemical reaction is also described in the prior art. Wherein in situgeneration of gas bubbles is provided by the decomposition of chemicalscompounds, the decomposition suitably produces O₂, CO₂, N₂, H₂, orcombinations thereof.

Various gases in bubble form have been used to sensitise blastingagents, for example nitrogen, carbon dioxide, oxygen, and hydrogen. Itis also known to directly inject air or gas into the explosive mixture.Suitable gases for injection include air, oxygen, nitrogen, carbondioxide, hydrogen, and noble gases (such as Argon).

Alternatively, hollow gas-filled compressible particles such as glass orplastic micro balloons, or porous particles, or expanded polystyrene(EPS) or mixtures thereof are included. In related embodiments thecompressible material is any low-density material which has a specificgravity <1.0 g/cm³. In brief summary, examples of glass balloons can beseen in U.S. Pat. Nos. 4,326,900 and 3,447,978, and plastic microballoons in U.S. Pat. Nos. 4,820,361 and 4,547,234. These balloons aretypically 0.05 mm in diameter and have a bulk density of 100 g/L. Use ofexpanded polystyrene can be seen for example in U.S. Pat. Nos. 5,470,407and 5,271,779.

In one embodiment, the compressible material is gas-filled and selectedfrom small hollow microspheres of ceramic, glass or resinous materialsor porous materials, and combinations thereof, such as perlite or flyash.

Preferably the microspheres/micro balloons contain gas such as pentane,etc.

Suitably the microspheres are sized between about 20 to 2000 micron andhave a bulk density of less than 1000 g/L.

In alternative embodiments, the compressible material is a cellularmaterial, such as expanded polystyrene (EPS), polyurethane foam, cottonseeds, expanded pop corn, husks, and combinations thereof.

Examples of suitable hollow particles include small hollow microspheresof ceramic, glass and resinous materials such as phenol-formaldehyde,poly(vinylidene chloride)/poly(acrylonitrile) copolymers andureaformaldehyde. Examples of suitable hollow particles include Q-Cel,Envirospheres®, Cenospheres®, Expancel®, 3M, Extendospheres®, etc.Examples of porous materials include expanded minerals such as perlite,fly ash. A further example of a porous material is hollow particles thatare a by-product of coal fired power stations.

Typically, sufficient bubbles and/or hollow particles and/or porousparticles are used in the compositions of the present invention to givean explosive composition having a density in the range of from 0.3 to1.4 g/cm³.

For example, an explosive composition of the invention may have adensity of up to 1.4 g/cm³, up to 1.3 g/cm³, up to 1.2 g/cm³, up to 1.1g/cm³, up to 1.0 g/cm³, etc. An explosive composition of the inventionmay have a density of from 0.3 g/cm³, from 0.4 g/cm³, from 0.5 g/cm³,etc. Using conventional mixing techniques to provide bubbles in emulsionexplosive compositions often produce bubbles with a range of bubblesizes. For example, the bubbles often have diameters up to 2000 micronsand average bubble diameters of less than 300 microns are also common.By choice of suitable surfactants bubbles of smaller or larger diameterscan be produced. Thus by choice of an appropriate surfactant at adesired concentration the mean gas bubble diameter in the discontinuousgas phase may be controlled, and bubbles of 50 to 300 microns arepossible. For emulsified explosives the density range is suitably around0.60-1.30 g/cm³, and for watergels the density range is suitably between0.2-1.40 g/cm³. In an emulsified system the gas bubbles are suitably10-100 times larger than the disperse phase droplets. The oily phase islikely to be in contact the gas bubble, whereas the oxidiser (ordiscontinuous phase) does not.

Other types of sensitising materials can be used in the compositions ofthe invention, e.g. TNT, HMX, RDX, aluminium powder and silicon powderand combinations thereof (e.g. TNT, HMX, RDX and aluminium powder andcombinations thereof).

Density Stabilisers

The explosive compositions of the present invention comprise at leastone density stabiliser.

Generally, one or more density stabilisers are incorporated in an amountof up to about 15% w/w of the explosives composition, for example about0.01% w/w to about 10% w/w, e.g. about 1 to about 5% w/w, such as about1 to about 3% w/w. The one or more density stabilisers are preferablypresent in a concentration of about 0.01, 0.05, 0.1, 0.25, 0.5, 0.75, 1,1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, 4, 4.25, 4.5,4.75, 5, 5.25, 5.5, 5.75, 6, 6.25, 6.5, 6.75, 7, 7.25, 7.5, 7.75, 8,8.25, 8.5, 8.75, 9, 9.25, 9.5, 9.75, 10, 11, 12, 13, 14 or 15% w/w. Theone or more density stabilisers are preferably present in aconcentration of around 0.01 to 0.05, 0.05 to 0.1, 0.1 to 0.5, 0.5 to 1,1 to 1.5, 1.5 to 2, 2 to 2.5, 2.5 to 3, 3 to 3.5, 3.5 to 4, 4 to 4.5,4.5 to 5, 5 to 5.5, 5.5 to 6, 6 to 6.5, 6.5 to 7, 7 to 7.5, 7.5 to 8, 8to 8.5, 8.5 to 9, 9 to 9.5, 9.5 to 10, 10 to 11, 11 to 12, 12 to 13, 13to 14 or 14 to 15% w/w.

Preferably the density stabiliser is present at about 0.01% w/w to about10% w/w, e.g. about 1 to about 5% w/w, such as about 1 to about 3% w/w.

Preferred density stabilisers are phosphonates.

Phosphonates

Preferably the phosphonate(s) are in liquid form (e.g. dissolved insolution).

The phosphonate may have 1, 2, 3, 4, 5 or 6 pendant phosphonate groups,or more than 6 groups. In some embodiments, the phosphonate may have 1,2, 3, 4, 5, 6, 7, 8, 9 or 10 pendant phosphonate groups. Preferably thephosphonate has at least 3 pendant phosphonate groups, more preferably 5pendant phosphonate groups.

In certain embodiments, the phosphonate has the structure X—(PO₃Y₂)_(n),where X is selected from the group consisting of an optionallysubstituted alkyl, optionally substituted heteroalkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted alkenyl; optionally substituted aryl, optionallysubstituted heteroaryl; Y is H or a water-soluble cation; and n is 1 to10 (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10). Suitable optional substituentscan be selected from the group consisting of —OH, —COOH, halogen, —NH₂,—SH. In preferred embodiments, the phosphonate has the structureX—(PO₃Y₂)_(n), where X is an optionally substituted heteroalkyl,optionally substituted heterocycloalkyl or an optionally substitutedheteroaryl having at least two nitrogen atoms, preferably at least threenitrogen atoms, more preferably three nitrogen atoms; Y is H or awater-soluble cation; and n is 1 to 10 (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9,10). Suitable optional substituents can be selected from the groupconsisting of —OH, —COOH, halogen, —NH₂, —SH.

In some preferred embodiments the phosphonates suitable for use in theinvention are amine based, more preferably tertiary amine based.

Suitable water soluble-cations for phosphonate anions include alkalimetals (e.g. lithium, sodium, potassium), ammonium, substituted ammoniumand alkaline earth metals (e.g. calcium, magnesium). Preferred compoundshave n=1 to 2 and preferably Y is hydrogen, ammonium, sodium orpotassium or mixtures thereof. In one preferred embodiment, the densitystabiliser is a phosphonate which is diethylenetriamine pentamethylenephosphonic acid sodium salt (DTPMPA.Na.x, C₉H_(28-x)N₃O₁₅P₅Na_(x))—seeFormula I.

Examples of other suitable phosphonates include those falling within thescope of Formula II:

The various X groups may be the same or different.

Examples of other suitable phosphonates include:

Phosphonate (number of phosphonate groups) Structure Glyphosate (1)

Foscarnet (1)

Perzinfotel (1)

Selfotel (1)

N- (phosphonomethyl)iminodiacetic acid (PMIDA) (1)

2-carboxyethyl phosphonic acid (CEPA) (1)

vinylphosphonic acid (1)

2-phosphonobutane-1,2,4- tricarboxylic acid (PBTC) (1)

aminomethylphosphonic acid (AMPA) (1)

2-hydroxyphosphonoacetic acid (HPAA) (1)

hydroxyethylidene-1,1- diphosphonic acid (HEDP) (2)

hydroxyethylamino- di(methylene phosphonic acid) (HEMPA) (2)

N,N- bis(phosphonomethyl)glycine (BPMG) (2)

aminotris(methylenephosphonic acid) (ATMP) (3)

ethylenediamine tetra(methylene phosphonic acid) (EDTMP) (4)

hexamethylene diamine tetra (methylene phosphonic acid) (HMDTMP) (4)

polyamino polyether methylene phosphonic acid (PAPEMP) (4)

tetramethylenediaminetetra (methylenephosphonic acid) (TDTMP) (4)

hexamethylenediaminetetra (methylenephosphonic acid) (HDTMP) (4)

bis(hexamethylene triamine penta (methylene phosphonic acid)) (BHMTPMP)(5)

diethylenetriamine penta(methylene phosphonic acid) (DTPMP) (5)

Phytic acid (6)

and salts, solvates, dimers, stereoisomers thereof.

Without being bound by any one theory, the inventor contemplates thatsuitable phosphonates for use in the invention provide densitystabilisation via chelation or sequestration of impurities inherentlypresent within the explosive compositions contemplated herein (i.e.,providing “internal” stability). Additionally, suitable phosphonates foruse in the invention provide density stabilisation via chelation orsequestration of impurities that arise when the explosive composition isloaded into the blasthole and exposed to rock (i.e., providing“external” stability). It will be appreciated that the explosives of theinvention can be used in a wide range of surface and subsurfaceapplications, and in a range of different types of rock having differentmetalliferous minerals. One or more phosphonates described herein can beselected for use depending on the type of impurity (metal ion) presentin the rock to be blasted and/or whether the application is in hotreactive ground, which can affect the solubility of metal ions and/orthe pH.

Composition Stabilisers

Other composition stabilisers can also be used with the presentinvention.

Suitable composition stabilisers may be selected from the groupconsisting of phosphates, stannates and sulfites.

Suitable composition stabilisers also include EDTA and nitrates (e.g.sodium nitrate or potassium nitrate).

For example, stannates, sulphites, and nitrates, either as a separateentity or as a component of the density stability system such as, forexample, a mixture of phosphonates and nitrates.

Typically, the other composition stabiliser component(s) of thecompositions of the present invention are incorporated in an amount ofup to about 15% w/w, for example about 0.01% w/w to about 10% w/w, e.g.about 1 to about 5% w/w, such as about 1 to about 3% w/w of the totalcomposition.

Fuels for Watergels

The explosive compositions of the invention may comprise one or morefuels.

H₂O₂-based watergels can be prepared with either water-miscible or waterimmiscible fuels.

The skilled person will appreciate that there are many options availablefor use as a fuel. For example, depending on their origin, the fuel maybe a product of vegetable origin, such as sugars, molasses, vegetableoils or alcohols. Such fuels may be regarded as sustainable fuels. Otherfuels can be sourced from the petrochemical industry, as for examplediesel, paraffinic oils or mineral oil, organic acids, ethers, esters,amine nitrates, urea, hexamine, etc. Other fuels may be silicone oils,etc. Suitable fuels for use in the compositions of the invention areglycerol, sugar, syrup, alcohol, carbon, ground coal, waxes, oils suchas corn, cottonseed, olive, peanut, or fatty acid oils. Suitablesustainable fuels for use in the compositions of the invention mayinclude, sugar molasses, vegetable oil, alcohol, oils such as corn,cottonseed, olive, peanut, fatty acid oils, or gums. Other fuels may beselected from ethylene glycol, glycerol, propylene glycol, and/orformamide Preferably, the sustainable fuel is glycerol. The compositionmay comprise between 15 and 25% w/w sustainable fuel, e.g., between 15and 20%, or between 20 and 25% w/w. The composition may alternativelycomprise less than 40% w/w sustainable fuel, less than 30%, less than25%, or less than 20% w/w sustainable fuel, e.g., 5%, 10%, 15%, 20%,25%, 30%, 35% or 40% w/w sustainable fuel. Alternatively, the abovefuels can also split into water-soluble and water-insoluble fuels.

Water-miscible fuels which can be used with the present invention can beselected from the group consisting of: glycerol, sugar, amine nitrates,hexamine and urea.

Water immiscible fuels which can be used with the present invention canbe selected from the group consisting of: aliphatic, alicyclic andaromatic compounds and mixtures thereof which are in the liquid state atthe formulation temperature. Suitable organic fuels may be chosen fromfuel oil, diesel oil, distillate, kerosene, naphtha, waxes, (e.g.microcrystalline wax, paraffin wax and slack wax) paraffin oils,benzene, toluene, xylenes, asphaltic materials, polymeric oils such asthe low molecular weight polymers of olefins, vegetable oils, animaloils, fish oils, and other mineral, hydrocarbon or fatty oils, andmixtures thereof. Preferred organic fuels are liquid hydrocarbonsgenerally referred to as petroleum distillates such as gasoline,kerosene, fuel oils, paraffin oils and vegetable oils or mixturethereof.

Typically, the water miscible or water-immiscible fuel of the watergelcomposition of the present invention comprises from 5 to 30% by weightand preferably 10 to 25% by weight of the total composition. Preferablythe fuel is included in a concentration of about 5, 7, 8, 10, 12, 15,20, 25, 30, 35, 40, 45, or 50% (w/w). Preferably the fuel is included ina concentration of between about 5 to 10, 10 to 15, 15 to 20, 20 to 25,25 to 30, 30 to 35, 35 to 40, 40 to 45, or 45 to 50% (w/w).

In one embodiment, the water-immiscible fuel is included at 7 to 25% w/wof the total composition.

In one embodiment, the water-miscible fuel is included at 8 to 25% w/wof the total composition.

Fuels for Emulsions

The explosive compositions of the invention may comprise one or morefuels.

H₂O₂-based emulsions can be prepared with water-immiscible fuels.

The fuel can be any fuel such as diesel fuel, and/or oil distillates.Alternatively, it can be paraffinic, mineral, olefinic, naphthenic,animal, vegetable, fish and silicone oils. Other types of fuels arebenzene, toluene, xylenes, asphaltic materials and the likes. The fuelmay be a sustainable fuel. Suitable sustainable fuels for use inemulsions may include vegetable oil, oils such as corn, cottonseed,olive, peanut, or fatty acid oils. The composition may comprise between15 and 25% w/w sustainable fuel, e.g., between 15 and 20%, or between 20and 25% w/w. The composition may alternatively comprise less than 40%w/w sustainable fuel, less than 30%, less than 25%, or less than 20% w/wsustainable fuel, e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35% or 40% w/wsustainable fuel.

The water-immiscible organic phase component of the composition of thepresent invention comprises the continuous “oil” phase of thewater-in-oil emulsion and is the fuel. Suitable organic fuels includealiphatic, alicyclic and aromatic compounds and mixtures thereof whichare in the liquid state at the formulation temperature. Suitable organicfuels may be chosen from recycled lubricant distillates, recycled oildistillates, fuel oil, diesel oil, distillate, kerosene, naphtha, waxes,(e.g. microcrystalline wax, paraffin wax and slack wax) paraffin oils,benzene, toluene, xylenes, asphaltic materials, polymeric oils such asthe low molecular weight polymers of olefins, vegetable oils, animaloils, fish oils, and other mineral, hydrocarbon or fatty oils, andmixtures thereof. Preferred organic fuels are liquid hydrocarbonsgenerally referred to as petroleum distillates such as gasoline,kerosene, fuel oils, paraffin oils and vegetable oils or mixturethereof.

Typically, the organic fuel or continuous phase of the H₂O₂-basedemulsion composition of the present invention comprises from 2 to 20% byweight and preferably 3 to % 20% by weight of the total composition.Preferably the organic fuel is included in a concentration of about 2,4, 6, 8, 10, 12, 14, 16, 18, or 20% (w/w). Preferably the organic fuelis included in a concentration of between about 2 to 4, 4 to 6, 6 to 8,8 to 10, 10 to 12, 12 to 14, 14 to 16, 16 to 18, or 18 to 20% (w/w).

Secondary Fuels for Watergels and Emulsions

If desired, other optional fuel materials, hereinafter referred to assecondary fuels, may be incorporated into the compositions of thepresent invention.

Examples of secondary fuels include finely divided solids. Examples ofsecondary fuels also include water-miscible organic liquids. Examples ofsolid secondary fuels include sulfur; aluminium; and carbonaceousmaterials such as gilsonite, comminuted coke or charcoal, carbon black,resin acids such as abietic acid, vegetable products such as starch, nutmeal, grain meal and wood pulp and combinations thereof. Examples ofsecondary fuels include sugars such as glucose and dextrose. Examples ofsecondary fuels further include recycled plastic waste.

Typically, the optional secondary fuel component of the compositions ofthe present invention comprise from 0 to 20% w/w of the totalcomposition, e.g. at 0.1 to 12% w/w.

Thickeners

The explosive compositions of the invention may comprise one or morethickeners. More particularly, the watergel explosive compositions ofthe invention may comprise one or more thickeners.

Because bubbles of gas and materials enclosing gas have a relatively lowdensity, they will tend to migrate towards the surface of the column ofexplosive if the viscosity of the H₂O₂-based explosive composition isnot capable of maintaining the sensitising material homogeneouslydispersed throughout. Migration of the sensitising material towards thesurface is undesirable as it may render the explosive too insensitive toinitiation, and therefore the explosive composition may not deliver theenergy and gases needed to break and move the rock as required or evenworst, the explosive may undergo a misfire. One way to ameliorate thisissue is to formulate the explosive composition into a watergel. Thesetypes of compositions can be formulated with different levels ofviscosity by using a thickener. Viscosities can be selected to generallyretain the sensitising material in a homogeneously dispersed statethroughout the composition.

If desired the aqueous solution of the compositions of the presentinvention may comprise thickeners which optionally may be crosslinked.Any conventional thickener may be used with the present invention. Thethickeners, when used in the compositions of the present invention, aresuitably polymeric materials, especially gum materials typified by thegalactomannan gums such as locust bean gum or xanthan gum or alginategum or derivates of alginate gum or guar gum or derivatives thereof suchas hydroxypropyl guar gum. The thickener may be selected from gumsincluding natural gums, such guar gum, xanthan gum, sodium alginate,carboxymethylcellullose, methylcellulose and the like. Other useful, butless preferred, gums are the so-called biopolymeric gums such as theheteropolysaccharides prepared by the microbial transformation ofcarbohydrate material, for example the treatment of glucose with a plantpathogen of the genus Xanthomonas typified by Xanthomonas campestris.Other useful thickeners include synthetic polymeric materials and inparticular synthetic polymeric materials which are derived, at least inpart, from the monomer acrylamide. An example of a synthetic thickeneris polyacrylamide. Inorganic thickeners, such as fumed silica, clays andcarbosil, may also be used, or a combination thereof. Suitably thethickener is selected from locust bean gum, guar gum, hydroxypropyl guargum, sodium alginate and heteropolysaccharides, and combinationsthereof.

Typically, the thickener component of the compositions of the presentinvention comprises from 0 to 5% by weight of the total composition,e.g. from 0.5 to 5% w/w, e.g. from 0 to 2% w/w of the total composition,e.g. from 0.1 to 2% by weight of the total composition.

Crosslinkers

Crosslinkers can also be used with the present invention.

Thickeners in combination with crosslinkers can improve the waterresistance and mechanical strength of the explosive. It is convenientfor this purpose to use conventional crosslinking agents such as zincchromate or a dichromate either as a separate entity or as a componentof a redox system such as, for example, a mixture of potassiumdichromate and potassium antimony tartrate. Salts of Ca, Ti, Sb can alsobe used as crosslinkers.

In one embodiment the crosslinker is selected from salts containingzinc, calcium, titanium, antimony, chromium, borate and dichromate andcombinations thereof.

Typically, the crosslinker component of the compositions of the presentinvention comprises from 0 to 3% w/w, e.g. from 0 to 0.1% w/w of thetotal composition, e.g. from 0.1 to 1% w/w of the total composition,e.g. from 1 to 2% w/w of the total composition, e.g. from 2 to 3% w/w ofthe total composition.

Emulsifiers

The explosive compositions of the invention, when prepared as emulsionform, may comprise one or more emulsifiers.

H₂O₂-based emulsion compositions are made of a discontinuous phase ofoxidising material that is dispersed in a continuous phase of an organicfuel in the presence of one or more emulsifiers. The emulsifier isadapted or chosen to maintain phase separation.

The emulsifier component of the composition of the present invention maybe chosen from the wide range of emulsifiers known in the art for thepreparation of water-in-oil emulsion explosive compositions. Examples ofsuch emulsifiers include polyisobutylene succinic anhydride (PIBSA)reacted with amines; other emulsifiers examples are alcohol alkoxylates,phenol alkoxylates, poly(oxyalkylene) glycols, poly(oxyalkylene) fattyacid esters, amine alkoxylates, fatty acid esters of sorbitol andglycerol, fatty acid salts, sorbitan esters, poly(oxyalkylene) sorbitanesters, fatty amine alkoxylates, poly(oxyalkylene) glycol esters, fattyacid amides, fatty acid amide alkoxylates, fatty amines, quaternaryamines, alkyloxazolines, alkenyloxazolines, imidazolines,alkyl-sulfonates, alkylarylsulfonates, alkylsulfosuccinates,alkylphosphates, alkenylphosphates, phosphate esters, lecithin,copolymers of poly(oxyalkylene) glycols and poly(12-hydroxystearicacid), and mixtures thereof.

Among the preferred emulsifiers are the 2-alkyl- and 2-alkenyl-4,4′-bis(hydroxymethyl) oxazoline, the fatty acid esters of sorbitol, lecithin,copolymers of poly(oxyalkylene) glycols and poly(12-hydroxystearicacid), and mixtures thereof, and particularly sorbitan mono-oleate,sorbitan sesquioleate, 2-oleyl- 4,4′-bis (hydroxymethyl) oxazoline,mixture of sorbitan sesquioleate, lecithin and a copolymer ofpoly(oxyalkylene glycol and poly (12-hydroxystearic acid), and mixturesthereof.

Typically, the emulsifier component of the composition of the presentinvention comprises up to 5% by weight of the total composition. Higherproportions of the emulsifier may be used and may serve as asupplemental fuel for the composition but in general it is not necessaryto add more than 5% by weight of emulsifier to achieve the desiredeffect. One of the advantages of the compositions of the presentinvention is that stable emulsions can be formed using relatively lowlevels of emulsifier and for reasons of economy it is preferable to keepthe amount of emulsifier used to the minimum required to have thedesired effect. The preferred level of emulsifier used is in the rangefrom 0.1 to 2.0% by weight of the total composition.

Surfactants

The explosive compositions of the invention when formulated as watergelsmay comprise one or more surfactants. In particular, one or moresurfactants may be employed when the explosive composition comprises adiesel-like fuel.

The surfactant component of the composition of the present invention maybe chosen from the wide range of surfactants known in the art for thepreparation of watergels and water-in-oil emulsion explosivecompositions. Examples of such surfactants include Sodium LaurylSulphate, Betaine CAB30, Sodium Coco Sulphate (Sodium Mono-C12-C18-AlkylSulfate), Alpha Olefin Sulphonate 46, Coconut diethanolamide, APG0810(Octyldecyl glucoside), and Cocamidopropyl Betaine.

Typically, the surfactant component of the composition of the presentinvention comprises up to about 0.5% by weight of the total composition,with about 0.25% w/w. used for Cocamidopropyl Betaine. Other oxidisersfor watergel and emulsion H₂O₂-based explosive compositions

It lies within the invention that there may also be incorporated intothe H₂O₂-based watergel/emulsion compositions hereinbefore described oneor more other substances or mixtures of substances which are themselvessuitable as explosive materials.

As a typical example of such a modified compositions reference is madeto compositions wherein there is added to and mixed with anwatergel/emulsion composition as hereinbefore described up to 90% w/w ofan oxidizing salt such as ammonium nitrate or an explosive compositioncomprising a mixture of an oxidizing salt such as ammonium nitrate andfuel oil and commonly referred to by those skilled in the art as “ANFO”.The compositions of “ANFO” are well known and have been described atlength in the literature relating to explosives.

In particular, the explosive compositions of the invention optionallycomprise one or more other oxidisers (e.g. one other oxidiser, e.g. twoother oxidisers). Any suitable oxidiser can be used. For example, theone or more other oxidiser(s) are suitably selected from the groupconsisting of nitrate salts, perchlorate salts, sodium peroxide andpotassium peroxide and optionally nitric acid.

Nitrate salts may be selected from the group consisting of ammoniumnitrate, sodium nitrate, calcium ammonium nitrate, calcium nitrate,potassium nitrate, barium nitrate and magnesium nitrate.

Perchlorate salts may be selected from the group consisting of ammoniumperchlorate, sodium perchlorate, potassium perchlorate, bariumperchlorate, magnesium perchlorate and calcium perchlorate (e.g.ammonium perchlorate and sodium perchlorate).

In one embodiment the one or more other oxidiser(s) are selected fromthe group consisting of nitrate salts and perchlorate salts. In oneembodiment the one or more other oxidiser(s) are selected from nitratesalts. In one embodiment the one or more other oxidiser(s) are selectedfrom the group consisting of AN, CAN and SN. In one embodiment the oneor more other oxidiser(s) are selected from the group consisting of CAN,CN and SN. In one embodiment the one or more other oxidiser(s) areselected from the group consisting of CAN and SN. In one embodiment theother oxidiser is CAN. In one embodiment the other oxidiser is SN. Inone embodiment the other oxidiser is CN. In one embodiment, the one ormore other oxidiser(s) do not include AN. In other words, in oneembodiment, the explosive composition is devoid of AN.

The compositions of the invention comprise from greater than 0 and up toabout 90% w/w of one or more other oxidisers, such as from about 0.1% toabout 75% w/w. For example, compositions of the invention may comprisefrom greater than 0, from 0.1%, from 1%, from 10%, from 20%, from 30%,from 40%, from 50%, or from 60% w/w up to 90% w/w of one or more otheroxidisers, e.g., compositions of the invention may comprise from 1 to20%, from 20 to 40%, from 15 to 35%, from 35 to 55%, from 30 to 70%,from 40 to 70%, or from 50 to 80% w/w of the one or more otheroxidisers. For example, compositions of the invention may comprise up to90%, 80%, 75%, 70%, 65%, 60%, 50%, 40%, 30%, 20% w/w, etc of one or moreother oxidisers, or may comprise about 90%, 80%, 75%, 70%, 65%, 60%,55%, 50%, 45%, 40%, 30%, or 20% w/w of one or more other oxidisers. Itwill be understood that the explosive compositions herein comprise oneor more oxidisers according to the foregoing amounts or ranges in total,and as such, where more than one oxidiser is used, each oxidiser may bepresent in any suitable amount within the foregoing amounts or rangessuch that the total mass of the oxidisers adds up to the specifiedamount or range.

It will be appreciated that the oxidiser can be in the form of a mixtureof solid and liquids. To explain, typically the oxidiser will besolubilised in water when used at a relatively low concentration, and ifpresent at higher concentrations beyond the solubility of the oxidiser,then the oxidiser will be solubilised and in a solid form. In someembodiments, the oxidiser is fully solubilised (or substantially fullysolubilised) in the composition. In such embodiments, excess solidoxidiser, e.g., in the form of prills, may be added. In otherembodiments, the oxidiser is only partially solubilised in thecomposition, in which case solid oxidiser (e.g., in the form of solidprills) may be added just prior to detonation such that there isinsufficient time for the prills to solubilise substantially. Theoxidiser can be in a liquid:solid ratio of between 100:0 to 20:80, andany ratio in between. For example, the liquid:solid ratio may be between100:0 and 70:30, or between 80:20 and 60:40, or between 70:30 and 40:60,or between 5:50 and 30:70, or of 100:0, 70:30, 60:40, 50:50, 45:55,40:60; or 20:80.

It also lies within the invention to have as a further explosivecomponent of the composition well known explosive materials comprisingone or more of for example trinitrotoluene, nitroglycerine orpentaerythritol tetranitrate.

It will also be appreciated that these other oxidisers can be used topartially replace H₂O₂ in the H₂O₂ compositions. Examples of suchoxidisers are nitrate salts, perchlorate salts, sodium/potassiumperoxide, etc.

Ratios of Oxidisers:Fuel

In one embodiment, the explosive composition may comprise a ratio ofH₂O₂:one or more other oxidisers in the range between 100:1 to 30:70.

In one embodiment, the explosive composition may comprise a ratio ofH₂O₂ (or H₂O₂+one or more oxidisers):fuel in the range between 87:13 to64:36.

In one embodiment, the explosive composition may comprise a ratio ofH₂O₂ (or H₂O₂+one or more oxidisers):fuel:water in the range between60:20:20 to 72:24:4.

Energy Deferments

The explosive compositions of the invention may optionally comprise oneor more energy deferments. Energy deferments include metal oxides suchas aluminium oxide.

Energy Diluents

The explosive compositions of the invention may optionally comprise oneor more energy diluents.

In the context of this invention, energy diluents are inert materialsthat have minimal contribution to the detonation process and can be usedto replace part of the energetic material in the composition andtherefore reduce the energy output of the H₂O₂-based explosive.

In some cases these energy diluents may increase, decrease or not alterthe density of the H₂O₂-based composition. In some cases, these energydiluting agents are able to reduce the density of the H₂O₂-basedcomposition without increasing the sensitivity.

Examples of these diluents materials are EPS (with particle size largerthan 2 mm in diameter), granulated/shredded rubber (from tyres), cottonseeds, saw dust, husk, expanded popcorn, plastic beads, wool meal,bagasse, peanut and oat husks, peanut shells etc. U.S. Pat. No.5,409,556 describes some example of these energy reducing agents. In oneembodiment the energy diluting agent is selected fromgranulated/shredded tyres, rubber, expanded rice, expanded popcorn,expanded wheat, and combinations thereof. These materials could also beused in combination with sensitisers to offer more flexibility (as shownin U.S. Pat. No. 5,470,407) as far as the performance properties of theH₂O₂-based explosive is concerned.

Therefore, another advantage of the H₂O₂-based explosive is that theperformance properties of the explosive can be altered to suit thecharacteristics of the blasting site.

Possible variations of this general procedure will be evident to thoseskilled in the art of the preparation of emulsion explosivecompositions.

Watergel or emulsion H₂O₂-based explosive compositions made according tothe present invention include energy diluents in concentration between0-800% by volume (i.e. the volume can be increased by 8×). As a result,the use of the additives (sensitiser and energy diluents), provides abetter control of the density, VOD and energy delivery in the groundbeing blasted.

Therefore, an additional advantage of the H₂O₂-based explosive is thatit could be used in a range of density between about 0.1 g/ml to about1.4 g/ml (e.g. between about 0.3 g/cm³ to about 1.4 g/cm³.

In one preferred embodiment the H₂O₂-based explosive compositions of theinvention comprise the following components: H₂O₂:fuel:water in therange between 25%:5%:70% to 73%:11%:16%.

Density of the Explosive Compositions

Suitably the final density is controlled with sensitiser to around 0.3to 1.4 g/cm³.

Suitably the density of the composition is formulated to be around 0.3,0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, or 1.4 g/cm³. Suitablythe final density of the composition is formulated to be between around0.3 to 0.4, 0.4 to 0.5, 0.5 to 0.6, 0.6 to 0.7, 0.7 to 0.8, 0.8 to 0.9,0.9 to 1.0, 1.0 to 1.1, 1.1 to 1.2, 1.2 to 1.3, or 1.3 to 1.4 g/cm³. Insome embodiments the density is controlled to a predetermined targetvalue by selection of the ratios of the components of the composition.For example, by balancing the concentration of a component which reducesthe density, such as hollow microspheres, and one that has a relativelyhigh density, such as nitrate prills.

pH of the Explosive Compositions

The pH of the emulsion explosive compositions of the present inventionis not narrowly critical. However, in general the pH is between 0 and 8and suitably the pH is between 1 and 6, and may be controlled bysuitable addition of conventional additives, for example inorganic ororganic acids and salts.

Viscosity of the H₂O₂-Based Compositions

The viscosity of the H₂O₂-based compositions (watergel or emulsion type)will be discussed in terms of apparent viscosity. Where used herein theterm “apparent viscosity” refers to viscosity measure using a BrookfieldRVT viscometer, #7 spindle at 50 r.p.m.

It is preferred in the process of the present invention that theexplosive composition of the water-in-oil emulsion explosive particleshave an apparent viscosity greater than 10 Pa*s (Pascal*second) prior tothe entrainment of gas bubbles. Apparent viscosity is more preferably inthe range 10 to 50 Pa*s. A more preferred viscosity range for theentrainment of gas bubbles by mechanical mixing is from 10 to 35 Pa*s.The range 10 to 25 Pa*s provides the most efficient entrainment of gasbubbles by mechanical mixing.

Preferably the explosive composition of the invention can be easilypumped.

Oxygen Balance of the Explosive Compositions

“Oxygen balance” (OB) is a term of the art which is used to indicate thedegree to which an explosive can be oxidised. An OB close to zero ispreferred when formulating mining explosives, such that no reactant isin excess during the detonation process, and therefore the expectedproducts are nitrogen, water and carbon dioxide. If the oxygen balanceis far from zero, some part of the reactant materials will not react andinstead, those unreacted material absorb/sink heat from the detonationreaction, which in turn will cause the explosive to underperform. Forexample, some prior art compositions are unsuitable for combustion, asthey lack fuel (and therefore the OB is too positive) and thecomposition cannot burn.

Suitably the amount of fuels materials in the explosive composition canbe adjusted so the composition has a final oxygen balance between +10and −10, e.g. between +5 and −5.

Preparation of Composition

According to a second aspect, the present invention provides a method ofpreparing an explosive composition according to the first aspect, themethod comprising: combining H₂O₂, and fuel and one or more densitystabilisers, and optionally one or more other oxidisers and/or, asensitiser, and one or more density stabilisers.

The H₂O₂-based compositions of the present invention may be prepared bya number of methods.

In one preferred method of manufacture, the H₂O₂-based watergel typecompositions may be prepared by combining H₂O₂ with a densitystabiliser, water miscible fuels, and thickeners until the thickenerstarts increasing the viscosity of said composition. Once the watergelis formed, solid ingredients (fuels, energy diluting agents, etc) areoptionally mixed into said watergel. Sensitisers can be mixed into saidwatergel capable in an amount capable to sensitise the watergel.Finally, sensitising agents can be mixed into the oxidiser componentprior to mixing into said watergel.

In one preferred method of manufacture the H₂O₂-based emulsion typecompositions may be prepared by: combining hydrogen peroxide with adensity stabiliser, the water-immiscible organic phase, a water-in-oilemulsifier, with rapid mixing to form a water-in-oil emulsion; thenmixing until the emulsion is uniform. Once the emulsion is formed, solidingredients (fuels, energy diluting agents, etc) are optionally mixedinto said watergel. Sensitisers are mixed into said emulsion in anamount capable of sensitising said watergel. Finally, sensitising agentscan be mixed into the oxidiser component prior to mixing into saidemulsion.

Preparation of Watergel H₂O₂-Based Explosive Composition

Watergel explosive compositions made according to the present inventionpreferably include H₂O₂ in concentrations between 10-64% by weight.

It will also be appreciated that other oxidisers can be combined withH₂O₂, as discussed above. For example nitrate salts, perchlorate salts,amine nitrates, sodium/potassium peroxide, etc., can be alsoincorporated in combination with H₂O₂.

The skilled person will appreciate that there are many options that areavailable for use as a fuel. For example the fuel may be a product ofvegetable origin, such as sugars or molasses, alcohols, organic acids,ethers, esters, urea, hexamines, etc. Alternatively, it may be a productderived from crude oil such a diesel, paraffinic oils or mineral oil,etc. Other fuels may be silicone oils, etc.

Secondary fuels may be a solid hydrocarbon, such as coal and recycledplastic waste. It may also be a metallic fuel, such asaluminium/silicon, etc, or gilsonite, comminuted coke or charcoal,carbon black, resin acids such as abietic acid, vegetable products suchas starch, nut meal, grain meal and wood pulp; or nitrogen compoundssuch as amides, amines, etc.

Preferably the amount of these fuels materials in the formulation can beadjusted so the H₂O₂-based composition has an oxygen balance between 3and −10 and the H₂O₂-based composition can be easily pumped. Thepreferred fuels are oil distillates, diesel-like hydrocarbons, glycerol,sugar, syrup, alcohol, carbon, ground coal, waxes, oils such as corn,cottonseed, olive, peanut, or fatty acid oils.

It will be appreciated that for an H₂O₂-based composition in accordancewith the invention to be functional, it is important that gas bubblesare homogeneously distributed throughout the composition. It is alsoimportant that once distributed throughout, the gas bubbles should bemaintained in a homogenous distribution throughout the composition, i.e.little or no segregation or settling, and that the density be maintainedor stabilised to increase the sleep time. In accordance with the presentinvention this may be achieved by formulating the explosive as a stablewatergel and including a density stabiliser. Formation of watergelcompositions is conventional in the art and one skilled in the art willbe familiar with the various forms that may be produced. Typically thiswill involve the use of a thickener that acts on the liquid oxidantcomponent of the composition. Herein the term “thickener” is alsointended to include gelling agents, crosslinking agents, and the like.

As discussed above, any conventional thickener may be used with thepresent invention. The thickener may be selected from natural gums, suchguar gum, xanthan gum, sodium alginate, carboxymethylcellullose,methylcellulose and the like. Synthetic thickeners, such polyacrylamide,may also be used. Inorganic thickeners, such as fumed silica, clays andcarbosil, may also be used, or a combination thereof.

Crosslinkers can also used with the present invention. Thickeners incombination with crosslinkers can improve the water resistance andmechanical strength of the H₂O₂ -based explosive. Examples ofcrosslinkers are those from antimony, calcium, titanium, chromium,borate salts and dichromate salts, etc.

Various additional ingredients, familiar to those skilled in the art,may be employed in the formulation of the invention.

Preparation of Water-In-Oil H₂O₂-Based Explosive Composition

Water-in-oil explosive compositions made according to the presentinvention include hydrogen peroxide in concentration between 10-85% byweight. It will also be appreciated that other oxidisers can be combinedwith H₂O₂, as discussed above. For example nitrate salts, perchloratesalts, amine nitrates, sodium/potassium peroxide, etc., can be alsoincorporated in combination with H₂O₂.

The fuel can be any fuel such as diesel fuel, recycled oil distillates,and diesel-like distillates. Alternatively it can be paraffinic,mineral, olefinic, naphtenic, animal, vegetable, fish and silicone oils.Other types of fuels are benzene, toluene, xylenes, asphaltic materialsand the likes.

Secondary fuels may be a solid hydrocarbon, such as coal and recycledplastic waste. It may also be a metallic fuel, such asaluminium/silicon, etc, or gilsonite, comminuted coke or charcoal,carbon black, resin acids such as abietic acid, vegetable products suchas starch, nut meal, grain meal and wood pulp; or nitrogen compoundssuch as amides, amines, etc.

Preferably the amount of these fuels materials in the formulation can beadjusted so the H₂O₂-based composition has an oxygen balance between 3and −10 and the H₂O₂-based composition can be easily pumped.

In relation to sensitisation, similar considerations apply towater-in-oil explosive compositions as the watergel explosivecompositions discussed above, namely preferably the gas bubbles arehomogeneously distributed throughout the composition. In accordance withthe present invention this is achieved by formulating the explosive as astable water-in-oil emulsion. Formation of emulsified explosives isconventional in the art and one skilled in the art will be familiar withthe various forms may be produced. Typically this will involve the useof an emulsifier, which is adapted to keep the oxidiser dispersedthroughout the continuous organic phase (fuel).

Emulsifiers commonly used in emulsion explosive compositions includesorbitan mono oleate, sorbitan sesquioleate, poly isobutylene succinicanhydrides (PIBSA) and amino derivatives of PIBSA, PIB-lactone and itsamino derivatives, fatty acid salts, lecithin, etc.

Use of the Compositions

According to a third aspect, the present invention provides use of anexplosive composition according to the first aspect to break and moveground, e.g. in mining operations.

According to a fourth aspect, the present invention provides the use ofone or more density stabilisers to improve the sleep time of anexplosive composition in reactive or metalliferous ground wherein theexplosive composition comprises H₂O₂ and fuel.

FURTHER EMBODIMENTS OF THE INVENTION

According to an embodiment of the present invention, a method ofpreparing an explosive composition is provided comprising: combininghydrogen peroxide a density stabiliser and a sensitiser, wherein thesensitiser comprises a compressible material and/or bubbles of gas. Itwill also be appreciated that the invention relates to a method ofpreparing an explosive composition comprising combining hydrogenperoxide and one or more compounds which produce a sensitiser.

According to a further embodiment of the present invention, use of anexplosive composition is provided comprising hydrogen peroxide and adensity stabiliser and a sensitiser, wherein the sensitiser comprises acompressible material and/or bubbles of gas. It will be appreciated thatthe composition of the invention can be used for many purposes, but inparticular to break and move ground in mining operations.

According to yet a further embodiment, the present invention provides asensitised and sleep-time enhanced explosive composition that delaysauto-sensitisation comprising H₂O₂, compressible material and/or bubblesof gas, and a density stabiliser.

In some embodiments the present invention consists essentially of H₂O₂,fuel, density stabiliser, and a sensitiser, wherein the sensitisercomprises a compressible material and/or bubbles of gas. In otherembodiments the present invention consists essentially of H₂O₂, densitystabiliser, fuel, a sensitiser, a thickener and/or crosslinker, whereinthe sensitiser comprises a compressible material and/or bubbles of gas.In other embodiments the present invention consists essentially of H₂O₂,fuel, density stabiliser, a sensitiser, fuel, surfactant/emulsifier, athickener and/or crosslinker, wherein the sensitiser comprises acompressible material and/or bubbles of gas.

In certain aspects, the present invention provides an explosivecomposition comprising: from about 2 to about 25% w/w H₂O₂; from greaterthan 0 and up to about 90% w/w one or more other oxidisers, and adensity stabiliser.

In one embodiment, there is provided an explosive compositioncomprising: from about 2 to about 25% w/w H₂O₂; and from greater than 0and up to about 90% w/w of one or more of other oxidisers; and fromabout 15 to about 25% w/w of fuels, preferably sustainable fuels, and adensity stabiliser.

According to a preferred embodiment, the present invention provides anexplosive composition comprising: from about 2 to about 25% w/w H₂O₂;from greater than 0 and up to about 90% w/w of one or more otheroxidisers; a fuel phase; a thickener and/or crosslinker; a secondaryfuel; a sensitiser, and a density stabiliser.

In some embodiments, the composition comprises from about 5 to about 25%w/w H₂O₂. Preferably the one or more other oxidiser(s) is a salt or acidselected from the group consisting of nitrate salts, perchlorate salts,peroxide salts, or nitric acid. For example, the one or more otheroxidisers may be selected from the group consisting of nitrate salts,perchlorate salts, sodium peroxide, potassium peroxide and optionallynitric acid. The perchlorate salts may be selected from ammoniumperchlorate and sodium perchlorate. Preferably the salts are selectedfrom ammonium nitrate (AN), calcium nitrate (CN), calcium ammoniumnitrate (CAN), sodium nitrate (SN), NH₄ClO₄, NaClO₄, Na₂O₂, K₂O₂ ormixtures thereof. For example, the nitrate salts may be selected fromammonium nitrate, calcium nitrate and sodium nitrate. By way of furtherexample, the nitrate salts may be selected from calcium ammoniumnitrate, calcium nitrate and sodium nitrate. In one embodiment, theexplosive composition is devoid of AN. The one or more other oxidisersin the explosive composition may be selected from calcium nitrate andsodium nitrate. Preferably the explosive composition contains from 0.1to 75% w/w of one or more other oxidisers. In one embodiment, theexplosive composition contains from 0.1 to 75% w/w of dissolved salts.In a preferred embodiment, at least some of at least one of the one ormore other oxidisers is not fully dissolved in the explosive compositionbut is present as a solid oxidiser, e.g., in the form of powder orprills. In such an embodiment, the one or more other oxidisers that isat least partially present as a solid may be selected from the groupconsisting of AN, SN, CN, CAN, or mixtures thereof. The composition maycomprise a solid nitrate oxidiser, for example, in an amount of fromcontains from 0.1 to 70% w/w. The composition may comprise water. Thesolid nitrate oxidiser may be selected from the group of AN, SN, CAN ormixtures thereof.

In one embodiment, there is provided an explosive compositioncomprising:

-   -   from about 2 to about 85% w/w hydrogen peroxide; and    -   from about 2 to about 25% w/w of fuels, preferably sustainable        fuels; and    -   from about 0.25 to about 5 of DTPMPA.Na.x

According to a preferred embodiment, the present invention provides anexplosive composition comprising:

-   -   from about 2 to about 25% w/w hydrogen peroxide; and from        greater than 0 and up to about 90% w/w of one or more other        oxidisers; or from about 2 to about 85% w/w hydrogen peroxide;    -   from about 0.25 to about 3% w/w of DTPMPA.Na.x;    -   a fuel phase;    -   a thickener and/or crosslinker;    -   a secondary fuel; and    -   a sensitiser.

Preferably the composition comprises 50% w/w or less of water, or 30%w/w or less of water, or 25% w/w or less of water. The explosivecomposition may further comprise one or more other components selectedfrom the group consisting of sensitisers, fuels, secondary fuels, water,thickeners, crosslinkers, emulsifiers, energy diluents and optionallyother additives.

Preferably the explosive composition comprises a sensitiser. Preferablythe sensitiser comprises a compressible material and/or bubbles of gas,or comprises a gas entrapped material. The bubbles of gas may be formedin situ and consist of N₂, O₂, CO₂, NO, or H₂ bubbles or a mixturethereof. The gas entrapped material may be selected from glassmicroballoons, ceramic microballoons, plastic microballoons or EPS witha particle size smaller than 2 mm. The explosive composition preferablyhas a density controlled by adding a sufficient amount of sensitisersuch that the composition is detonation-sensitive. The density may becontrolled to around 0.3 to 1.4 g/cm³, or may be formulated to around0.3 to 1.4 g/cm³.

The composition may comprise a fuel, or it may comprise a fuel and asecondary fuel. The fuel may be a water soluble fuel. The water solublefuel may be selected from an amine nitrate or urea or a mixture thereof.The explosive composition may contain from 0.1 to 30% w/w of watersoluble fuel. The composition may contain between 13-25% w/w of the fuelphase. Preferably the fuel phase comprises one or more componentsselected from the group consisting of gums, glycerol, ethylene glycol,propylene glycol, sugar molasses, formamide or mixtures thereof. Forexample, the fuel phase may comprise one or more components selectedfrom the group consisting of gums, glycerol, ethylene glycol, propyleneglycol, formamide or mixtures thereof. The composition may comprise asustainable fuel. The sustainable fuel may be present in the compositionin an amount of between 15 and 25% w/w.

Preferably the composition is a watergel composition, in which case thecomposition may comprise a thickener or crosslinker. The composition maybe a watergel composition comprising a thickener and a crosslinker. Thethickener may be suspended in the fuel. The thickener may be selectedfrom the group consisting of guar gum, xanthan gum, sodium alginate,polyacrylamides, and polyvinyl alcohols. The composition may comprise acrosslinker selected from the group of antimony salts, chromic salts,phosphoric acid or mixtures thereof. The fuel phase may comprise one ormore water insoluble fuels selected from the group consisting of diesel,oils, vegetable oils, or mixtures thereof. Accordingly, the explosivecomposition may be formulated as an emulsion, in which case it maycomprise an emulsifier. The emulsifier may be mixed in the fuel. Theemulsifier may be selected from the group consisting of PIBSA-aminederivatives, SMO, lecithin or a mixture thereof.

Preferably the composition is formulated to have an oxygen balancebetween +10 to −10, e.g., the composition may have an oxygen balance ofbetween +5 and −5. The explosive composition may contain from 1 to 800%v/v of an energy reducing agent (i.e., diluent material). The energydiluent material may be selected from the group consisting of EPS, crumbrubber tyre, popcorn, and plastic beads. The hydrogen peroxide, one ormore other oxidisers and a fuel containing thickeners may be mixed untila thick material is formed, with a viscosity between 5-50 Pa*s. Thecomposition may have a viscosity of from 5 to 50 Pa*s.

Many advantages result from the inventive explosive compositions taughtherein. For example, certain formulations of the compositions of theinvention may be more convenient to prepare, more cost effectivecompared to existing explosive compositions, safer to produce and tostore, and/or capable of being produced in large quantities to meet thedemand from the mining industry. Added safety and broader application isprovided by the use of a density stabiliser to extend sleep-time. Thepresent invention is therefore a significant advance in the art. Theexplosive compositions of the invention utilise H₂O₂, which is asustainably-produced material that has a relatively low carbon footprintcompared to other types oxidisers used in the art. The composition mayalso use sustainable fuels, as opposed to current technology used in themining industry. To explain, current explosive compositions use a lowconcentration of fuel, which is typically sourced from the petrochemicalindustry. In contrast, the inventive explosive compositions disclosedherein are able to incorporate relative amounts of recycled fuel tocommercially available or prior art explosive compositions. Accordingly,the recycled fuels from the petrochemical industry is a significantadvance in the art. Additionally use of recycled fuels in thecomposition means that the amount of oxidiser material in theformulation can be balanced without affecting the detonation properties.

The present invention is counterintuitive to the common knowledge in theart. To explain, it is currently believed that it is impossible or verydifficult to stabilise the density of compositions that has a relativelyhigh concentration of H₂O₂. However, surprisingly, the present inventionprovides the ability to enhance the density stability of compositionsthat contain up to 42% w/w of H₂O₂. This aspect of the present inventionis a significant advance in the art. The present invention also providesthe ability to incorporate a relatively high amount of nitrates bymaking a watergel or emulsion, which already comprises H₂O₂/nitrate inthe aqueous phase, with a further solid nitrate phase in the form ofprills. Use of oxidiser in solid form enables some control over thedensity of the overall composition, and therefore provides some controlover the VOD, as will be discussed below.

The explosive compositions of the invention may also be formulated intoemulsion form. It will also be appreciated that the inventivecompositions of the invention may produce low amounts of NO_(x), and insome forms of the invention no NO_(x) at all.

The compositions of the invention are contemplated to provide severaladvantages over the prior art, such as better stability over time thanexplosive compositions comprising a higher percentage of H₂O₂. This isadvantageous in the context of both safety, storage, and application.More specifically, the “sleep time” (i.e. the time over which anexplosive deteriorates in situ such that its velocity of detonationdecreases below a defined useful limit of such an explosive compositionwhen it is in contact with rocks) is expected to be greater than anexplosive comprising a higher percentage of H₂O₂. By way of example, adensity-stabilised H₂O₂ composition according to the invention has beenmade and found to have a sleep time that is in excess of compositionswithout density stabilisers, and comparable/compatible for applicationin a commercially viable product, for example, a sleep time beyond 24hours or more. It is therefore contemplated that larger blasts arepossible because there is a longer time (e.g. several days) over whichexplosives can be loaded into many holes before the first-loadedexplosive becomes unstable in its hole. More holes can therefore beloaded before detonation.

Another advantage is that these compositions detonate when densitystabliisers are used. This is unexpected because of concerns thatdensity-stabilised compositions may not detonate. There are also safetyadvantages contemplated in using density stabilised compositions.

The present invention relates to a peroxide-based explosive compositionthat is preferably prepared as watergel or water-in-oil emulsion and issensitised.

Numerous embodiments are described in this patent application and arepresented for illustrative purposes only. The described embodiments arenot intended to be limiting in any sense. The invention is widelyapplicable to numerous embodiments, as is readily apparent from thedisclosure herein.

Table 1 lists the components of explosive systems discussed herein andprovides typical ranges for each:

TABLE 1 components for explosive systems discussed herein with typicalranges for each. Component (in % by weight of total composition exceptwhere Explosive technology indicated otherwise) Watergel Emulsion H₂O₂From 2 to 65 From 10 to 80 Density stabiliser From 0.1 to 5 From 0.1 to5 One or more other oxidiser From 0 to 90 From 0 to 90 Sensitiser (% byvolume) From 0.5 to 800* From 0.5 to 800* Fuels From 2 to 25 From 2 to25 Secondary fuels From 0.1 to 11 From 0.1 to 11 Water From 5 to 40 From5 to 40 Thickeners From 0.5 to 5 N/A Emulsifiers N/A From 0.5 to 5Additives 0.1 to 5 0.1 to 5 Energy diluents (% by From 0.1 to 300** From0.1 to 300** volume) Oxygen Balance From 5 to −5 From 5 to −5 Finaldensities (g/ml) 0.3 to 1.4 0.3 to 1.4 NOTE: it will be appreciated thatthe volume can be increased by 8× (*), and 3× (**), respectively.

Typical components for each type of explosive technology are listed inTable 2:

TABLE 2 Typical components of the present invention for each type ofexplosive technology. Explosive technology Component WatergelWater-in-oil emulsion Oxidiser(s) hydrogen peroxide (H₂O₂) hydrogenperoxide (H₂O₂) optionally nitrate salts optionally nitrate salts and/orperchlorate salts and/or perchlorate salts and/or sodium/potassiumand/or sodium/potassium peroxide peroxide Sensitiser gas bubbles(chemically gas bubbles (chemically generated or injected generated orinjected bubbles) and/or gas bubbles) and/or gas entrapped compressibleentrapped compressible materials materials Fuel Water miscible fuels,water Water miscible fuels, water immiscible fuels, water immisciblefuels, water soluble fuels or water- soluble fuels or water- insolublefuels insoluble fuels Surfactant water soluble surfactants water solublesurfactants or fuel-soluble surfactants or fuel-soluble surfactantsDensity e.g., Phosphonates e.g., Phosphonates. stabiliser CompositionPhosphates, Stannates, Phosphates, Stannates, stabiliser etc. etcAdditives crosslinkerss, catalysts for crosslinkers, catalysts forgassing, pH adjusters, gassing, pH adjusters, thickeners emulsifiersEnergy Granulated/shredded Granulated/shredded diluents rubber, expandedpopcorn, rubber, expanded popcorn, (optional) expanded rice, plasticexpanded rice, plastic beads, EPS >5 mm beads, EPS >5 mm Energy Metaloxides Metal oxides deferments (optional)

EXAMPLES

The present invention can be used for a variety of forms of explosivesprovided of course that the principles of the invention as describedherein are observed. The invention is further illustrated with referenceto the following examples.

Example 1

Hydrogen peroxide/fuel-based hydrogel formulations, containing aglycerol fuel phase, were calculated and hand-made containing 0-3% w/wDTMPMA.Na.X material (See Table 3 below).

DTMPMA.Na.X was first suspended in the oxidiser phase, then mixed withthe fuel phase of the formulation. Plastic pots (58 mL) were used tostore the gels (n=4) on laboratory benches at room temperature (25-35°C.). Formulation density vs DTMPMA.Na.X % w/w were determined for therange of 0-3% w/w. Over seven days, density measurements were taken andchange in density was calculated. Tests were terminated when gelsdisplayed compromised structure due to large gas bubble generation.

TABLE 3 Explosive compositions prepared according to the presentinvention. Composition (w/w % phosphonate) Component (w/w %) 0 1 2 3hydrogen peroxide 41.8 41.5 41.1 40.8 (100% w.w.) water 41.8 41.5 41.140.8 glycerol fuel 13.4 13 12.8 12.4 xanthan gum-based 3 3 3 3 explosivecompositions diethylenetriamine 0 1 2 3 pentamethylene phosphonic acidsodium salt (DTPMPA.Na.x)

The results are shown in FIG. 1 and FIG. 2. Whilst 0% w/w DTMPMA.Na.Xformulation degraded within two days, the tests were allowed to continueuntil decomposition of all gels was observed.

TABLE 4 Density (g · cm⁻³) vs time (days) for explosive compositionshaving varying levels of phosphonates. Density (g · cm⁻³) at CompositionTime (% w/w phosphonate) (days) 0 1 2 3 0 1.25 1.25 1.25 1.25 1 1.061.21 1.21 1.21 2 0.88 1.16 1.16 1.16 3 — 1.13 1.13 1.13 4 — 1.02 1.021.04 7 — 0.76 0.76 0.76 Note, 0% w/w phosphonate mixture collapsed byday 3.

TABLE 5 Density loss (% to initial) vs time for explosive compositionshaving varying levels of phosphonates. Density loss (% to initial) atComposition Time (% w/w phosphonate) (days) 0 1 2 3 0 0 0 0 0 1 15.2 1.22.2 3 2 29.6 4 5.2 7 3 — 7.4 8.2 9.4 4 — 16.6 16.6 16.6 7 — 40 40 40Note, 0% w/w phosphonate mixture collapsed by day 3.

Formulations without density-stabilised hydrogen peroxide degradedwithin 48 hours, whereas density-stabilised hydrogen peroxidecompositions at the same time period exhibited approx. 7 percent densityloss to the initial density. This is a significant and surprisingimprovement. This improvement to sleep time means that more blast holescan be loaded during a planned blast saving time and money, that thedetonation performance of the product has enhanced reliability, and thatthe product has improved safety due to the reduced likelihood of densityloss.

Example 2

Detonation performance analysis was carried out in field-rangeunconfined tests to assess the explosive capability and characteristicsof density-stabilised hydrogen peroxide compositions 81.35% w/w hydrogenperoxide (50% w/w), 12.65% w/w glycerol fuel, 3% w/w xanthan gum, and 3%w/w DTPMPA.Na.x formulation, incorporating varying % w/w GMB (3M™ K15Glass Bubbles) for required density (See table 4 below).

TABLE 6 Detonation testing of explosive compositions prepared accordingto the present invention. Density (g · cm⁻³) Component (w/w %) 0.83 1.01.03 1.05 1.08 hydrogen peroxide 39.4 39.8 40 40 40.06 (100% w/w) water39.4 39.8 40 40 40.06 glycerol fuel 12.25 12.35 12.4 12.45 12.46 xanthangum-based 2.9 2.9 2.925 2.9525 2.96 explosive compositionsdiethylenetriamine 2.9 2.9 2.925 2.9525 2.96 pentamethylene phosphonicacid sodium salt (DTPMPA.Na.x) GMB, (3M ™ K15) 3.15 2.25 1.75 1.6 1.5Average Velocity 3628 4210 4337 4334 4401 of Detonation (m · s⁻¹)

Triplicate samples were prepared of explosive compositions.

The results are shown in FIG. 3.

As can be seen from these examples, the density loss and instability ofthe hydrogen peroxide-based explosives was reduced, with the addition ofphosphonates, increasing the sleep-time of the formulations. The use ofhydrogen peroxide/fuel-based explosives prepared with the addition ofphosphonates results in a substantial improvement in the art of hydrogenperoxide/fuel-based explosives. Importantly, the addition of densitystabilisers as described herein does not adversely impact on thedetonation performance of the explosive composition.

Detonation Testing

Selected compositions were tested to determine detonation. 47 mmdiameter, clear high density (150 μm) polyethylene lay-flat tube by 1000mm in length and sealed on one end were used for gels. Detonation wasinitiated with a 25 g Pentex D Booster.

Duplicate VOD was measured using a Time Domain Reflectometry (TRD)-basedVOD instrument featuring a sample rate of under 4 uS and a nominalresolution of 90 Pico seconds. The VOD data indicate an acceptabledetonation performance for mining applications.

Example 3

Stabilised-hydrogen peroxide/fuel-based hydrogel formulations,containing a glycerol fuel phase, were calculated and hand-madecontaining 0-2% w/w Phytic Acid (PA). PA was first suspended in theoxidiser phase, then mixed with the fuel phase (3% xanthan gum) of theformulation. Plastic pots (˜58 mL) were used to store the gels (n=4) onlaboratory benches at room temperature (20-25° C.). Product density vsPA % w/w were established for the range of 0-5% PA. Over 13 days,density measurements were taken and change in density was calculated.Tests were terminated when gels displayed compromised structure due tolarge gas bubble generation. Whilst 3-5% w/w PA degraded within 5 days,the tests were allowed to continue until decomposition of all gels wasobserved.

Over two tests, of 10 days and 13 days respectively, it was observedthat all gels decreased in density. All initial gel densities wereapprox. 1.22 g·cm³. With increasing % w/w PA an associated increase ingel density was observed (FIG. 4 & FIG. 5). Gels containing 3-5% w/w PAdegraded within five days. At approximately seven days the rate ofdegradation of the nil-PA control appears to change, which may be anindicator of HP degradation nearing completion. Whilst 0.25% w/w PAdisplayed the least density loss over the time course (FIG. 6 & FIG. 7),statistically significant loss over 13 days was not determined betweennil-PA and 0.25% w/w PA gels (p-value=0.19). Over the measurement time,individual pot measurement standard deviations of replicants did notexceed 0.02 mL.

Formulations containing PA at concentrations of 0.25-0.75% w/w displayedincreased gel stability over 13 days. However, PA at concentrationsabove about 0.75% accelerated decomposition. After 13 days of roomtemperature bench-top storage, all gels, including mixtures containingPA, had lost at least 18% gel density when compared to initial density.

The skilled addressee will understand that the invention comprises theembodiments and features disclosed herein as well as all combinationsand/or permutations of the disclosed embodiments and features.

Although the invention has been described with reference to specificexamples, it will be appreciated by those skilled in the art that theinvention may be embodied in many other forms. In particular features ofany one of the various described examples may be provided in anycombination in any of the other described examples.

1. An explosive composition comprising: H₂O₂; fuel; and one or moredensity stabilisers of about 0.01% to about 10% w/w.
 2. The explosivecomposition according to claim 1, wherein the H₂O₂ is between about 2%to about 85% by weight.
 3. The explosive composition according to claim1, wherein the one or more density stabilisers are in an amount of about1% to about 5% w/w.
 4. The explosive composition according to claim 1,wherein the one or more density stabilisers comprises a phosphonatehaving the structure X—(PO₃Y₂)_(n), wherein: X is selected from thegroup consisting of an optionally substituted alkyl, optionallysubstituted heteroalkyl, optionally substituted cycloalkyl, optionallysubstituted heterocycloalkyl, optionally substituted alkenyl, optionallysubstituted aryl, and optionally substituted heteroaryl; Y is H or awater-soluble cation; and n is 1 to
 10. 5. The explosive compositionaccording to claim 4, wherein the phosphonate is selected from the groupconsisting of: phytic acid, aminotris(methylenephosphonic acid),bis(hexamethylene triamine penta (methylene phosphonic acid)),diethylenetriamine penta(methylene phosphonic acid),tetramethylenediaminetetra(methylenephosphonic acid),hydroxyethylidene-1,1-diphosphonic acid, hydroxyethylamino-di(methylenephosphonic acid), hexamethylene diamine tetra (methylene phosphonicacid), 2-hydroxyphosphono acetic acid, nitrilotrimethyl-phosphonic acid,polyamino polyether methylene phosphonic acid,2-phosphonobutane-1,2,4-tricarboxylic acid, glyphosate, foscarnet,perzinfotel, selfotel, N-(phosphonomethyl)iminodiacetic acid,2-carboxyethyl phosphonic acid, vinylphosphonic acid,aminomethylphosphonic acid, N,N-bis(phosphonomethyl)glycine, andtetramethylenediaminetetra(methylenephosphonic acid), and salts,solvates, dimers, and stereoisomers thereof.
 6. The explosivecomposition according to claim 4 wherein the phosphonate isdiethylenetriamine pentamethylene phosphonic acid sodium salt.
 7. Theexplosive composition according to claim 1, wherein the densitystabiliser retains the density of the explosive composition to within+/−10% of its initial density, and wherein the density is maintainedover a period of up to 10 days.
 8. (canceled)
 9. The explosivecomposition according to claim 7, wherein the density stabilisermaintains the velocity of detonation (VOD) to within +/−10% of theinitial VOD, and wherein the VOD is maintained over a period of up to 14days.
 10. (canceled)
 11. The explosive composition according to claim 1,further comprising 50% w/w or less of water.
 12. The explosivecomposition according to claim 1, further comprising one or morecomponents selected from the group consisting of: one or more otheroxidisers, a sensitiser, a secondary fuel, a thickener, a crosslinker,an emulsifier, and an energy diluent.
 13. The explosive compositionaccording to claim 12, wherein the sensitiser comprises a compressiblematerial and/or bubbles of gas.
 14. The explosive composition accordingto claim 13, wherein the bubbles of gas are formed in situ and consistof N₂, O₂, CO₂, or H₂ bubbles, or a mixture thereof.
 15. The explosivecomposition according to claim 13, wherein the compressible material isgas-entrapped material which is selected from glass microballoons,ceramic microballoons, plastic microballoons or expanded polystyrene(EPS) with a particle size smaller than 2 mm.
 16. The explosivecomposition according to claim 15, wherein a sufficient amount ofsensitiser is added such that the composition is detonation-sensitive,and wherein the density of the explosive composition is controlled toaround 0.3 to 1.4 g/cm³.
 17. (canceled)
 18. (canceled)
 19. The explosivecomposition according to claim 13 comprising from about 0.1% to about75% w/w one or more other oxidisers.
 20. (canceled)
 21. (canceled) 22.(canceled)
 23. The explosive composition according to claim 12, whereinthe thickener is selected from the group consisting of guar gum, xanthangum, sodium alginate, polyacrylamides, and polyvinyl alcohols. 24.(canceled)
 25. (canceled)
 26. The explosive composition according toclaim 12, wherein the composition is formulated as an emulsion or awatergel.
 27. The explosive composition according to claim 1, whereinthe explosive composition contains from 2% to 25% w/w fuel, wherein thefuel comprises one or more water insoluble fuels selected from the groupconsisting of diesel, oils, paraffinic oils, naphthenic oils, andvegetable oils, or mixtures thereof.
 28. (canceled)
 29. (canceled) 30.(canceled)
 31. (canceled)
 32. A method of preparing an explosivecomposition, the method comprising combining H₂O₂, fuel and one or moredensity stabilisers of about 0.01% to about 10% w/w.
 33. (canceled) 34.(canceled)